the fox news effect: media bias and voting* stefano dellavigna and

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING*

STEFANO DELLAVIGNA AND ETHAN KAPLAN

Does media bias affect voting? We analyze the entry of Fox News in cable

markets and its impact on voting. Between October 1996 and November 2000, the

conservative Fox News Channel was introduced in the cable programming of 20

percent of U. S. towns. Fox News availability in 2000 appears to be largely

idiosyncratic, conditional on a set of controls. Using a data set of voting data for

9,256 towns, we investigate if Republicans gained vote share in towns where Fox

News entered the cable market by the year 2000. We ﬁnd a signiﬁcant effect of the

introduction of Fox News on the vote share in Presidential elections between 1996

and 2000. Republicans gained 0.4 to 0.7 percentage points in the towns that

broadcast Fox News. Fox News also affected voter turnout and the Republican

vote share in the Senate. Our estimates imply that Fox News convinced 3 to 28

percent of its viewers to vote Republican, depending on the audience measure. The

Fox News effect could be a temporary learning effect for rational voters, or a

permanent effect for nonrational voters subject to persuasion.

I. INTRODUCTION

Does the media affect voting behavior? According to rational

expectation theories, voters ﬁlter out bias in reporting without

being persuaded on average [Bray and Kreps 1987]. Alterna-

tively, behavioral theories [De Marzo, Vayanos, and Zwiebel

2003] and cognitive linguistics theories [Lakoff 1987] suggest

that voters are subject to media persuasion. Understanding the

impact of the media is of interest not only for politics but also,

* George Akerlof, Stephen Ansolabehere, Lawrence M. Bartels, Robert Calo,

Arindrajit Dube, Edward Glaeser, Matthew Gentzkow, Alan Gerber, Jay Hamil-

ton, Lawrence Katz, Alan Krueger, Ulrike Malmendier, Marco Manacorda, Enrico

Moretti, Suresh Naidu, Torsten Persson, Sam Popkin, Riccardo Puglisi, Matthew

Rabin, Jesse Shapiro, Uri Simonsohn, Laura Stoker, David Stromberg, Daniel

Sturm, and audiences at Beijing University, Bonn University (IZA), Carnegie-

Mellon University, EUI (Florence), Fuqua, Harvard University (Economics De-

partment and Business School), IIES (Stockholm), LSE, Princeton University, UC

Berkeley, UC Davis, University of Chicago GSB, University of Munich (CES,

Germany), University of Rochester, Uppsala University (Sweden), Wharton, and

the NBER 2005 Political Economy and Labor Studies Meetings provided useful

comments. We also thank the editor (Edward Glaeser) and three referees for

detailed and helpful comments. We especially thank Jim Collins and Matthew

Gentzkow for providing the Scarborough data. Shawn Bananzadeh, Jessica Chan,

Marguerite Converse, Neil Dandavati, Tatyana Deryugina, Monica Deza, Dylan

Fox, Melissa Galicia, Calvin Ho, Sudhamas Khanchanawong, Richard Kim, Mar-

tin Kohan, Vipul Kumar, Jonathan Leung, Clarice Li, Tze Yang Lim, Ming Mai,

Sameer Parekh, Sharmini Radakrishnan, Rohan Relan, Chanda Singh, Matthew

Stone, Nan Zhang, Sibo Zhao, and Liya Zhu helped collect the voting and the cable

data. Dan Acland, Scott Baker, Thomas Barrios, Saurabh Bhargava, Avi Eben-

stein, Devin Pope, Anitha Sivasankaran, and Justin Sydnor provided excellent

research assistance.

Technology.

The Quarterly Journal of Economics, August 2007

1187

more generally, for models of belief updating. From a policy

perspective, if media bias alters voting behavior, deregulation of

media markets may have a large impact on political outcomes.

In this paper, we address this question empirically. We exploit

the natural experiment induced by the timing of the entry of the Fox

News Channel in local cable markets and consider the impact on

voting. The twenty-four-hour Fox News Channel (“Fox News” from

here on) was introduced by Rupert Murdoch in October 1996. Fox

News expanded rapidly to reach 20 percent of U. S. cities and an

audience of 17.3 percent of the U. S. population by June 2000 (Scar-

borough Research data).

The decentralized nature of the cable industry induced sub-

stantial geographical variation in access to Fox News. Cable

companies in neighboring towns adopted Fox News in different

years, creating idiosyncratic differences in access. Since Fox

News is signiﬁcantly to the right of all the other mainstream

television networks [Groseclose and Milyo 2005], the introduction

of Fox News into a cable market is likely to have had a signiﬁcant

effect on the available political information in that cable market.

This is true whether Fox News represents the political center and

the rest of the media the liberal wing, or Fox News represents the

right and the rest of the media the middle.

To analyze whether the change in political information af-

fects voting, we assemble a new panel of town-level data on

federal elections and match it with town-level data on cable

programming. We compare the change in the Republican vote

share between 1996 and 2000 for the towns that had adopted Fox

News by 2000 with those that had not. Conditional on a set of

geographic and cable controls, the availability of Fox News is

uncorrelated with town-level demographic controls and with

town-level voting patterns in 1996 and before 1996.

Our main result is that Fox News had a signiﬁcant impact on

the 2000 elections. The entry of Fox News increased the Repub-

lican vote share in presidential elections by 0.4 to 0.7 percentage

points, depending on the speciﬁcation. Since Fox News in 2000

was available in about 35 percent of households, the impact of Fox

News is estimated to be 0.15 to 0.2 percentage points, 200,000

votes nationwide. While this vote shift is small compared to the

3.5 percentage point shift overall in our sample between 1996 and

2000, it is still likely to have been decisive in the close presiden-

tial elections.

We check our identiﬁcation strategy with placebo speciﬁca-

1188 QUARTERLY JOURNAL OF ECONOMICS

tions; in particular, we show that availability of Fox News in 2000

did not affect the vote share between 1992 and 1996 or between

1988 and 1992, when Fox News did not yet exist.

We provide evidence that the Fox News effect varies with

town characteristics. The effect was smaller in towns with more

cable channels, which is consistent with a moderating effect of

competition [Mullainathan and Shleifer 2005]. In addition, Fox

News had a smaller effect in rural areas and in Republican

congressional districts, possibly because in these towns the share

of non-Republicans at risk of being convinced was smaller.

We also analyze whether Fox News affected voting in races

where Fox News did not cover the candidates directly, as in most

Senate races. This allows us to estimate whether the inﬂuence of

Fox News is candidate-speciﬁc or whether it extends to general

political beliefs. We ﬁnd that Fox News signiﬁcantly increased

the Republican vote share for the Senate by 0.7 percentage

points. Additionally, the effect is not signiﬁcantly larger for the

one Senatorial race that Fox News covered heavily, the New York

State race between Hillary Clinton and Rick Lazio. Fox News

appears to have induced a generalized ideological shift.

Finally, we consider whether the Fox News effect on presi-

dential elections was mainly a result of voters switching party

lines or of additional voter turnout to the polls. We ﬁnd that Fox

News signiﬁcantly increased voter turnout, particularly in the

more Democratic districts. The impact of Fox News on voting

appears to be due, at least in part, to the mobilization of voters

and particularly conservative voters in Democratic-leaning

districts.

Overall, we ﬁnd a sizeable impact of Fox News on the vote

share for Republicans. To quantify the persuasion rate of the

media, we incorporate information on the extent of viewership

and the share of Republicans in the Fox News audience. Using

two different audience measures from Scarborough Research

data, we compute the impact on the Fox News viewership of

availability of Fox News in local cable programming. The more

inclusive audience estimates imply that Fox News convinced

between 3 and 8 percent of its non-Republican viewers to vote

Republican, depending on the speciﬁcation. The more restrictive

audience measures imply persuasion effects between 11 and 28

percent. Exposure to more conservative coverage, therefore, had a

sizeable, and possibly large, persuasion effect.

We compare the persuasion rates estimated in our study with

1189THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

the persuasion rates implied by other studies of media effects on

political beliefs or voting.

These studies include ﬁeld experi-

ments on voter turnout [Green and Gerber 2004] and on party

choice [Gerber, Karlan, and Bergan 2006], laboratory experi-

ments involving exposure to political advertisements [Ansolabe-

here and Iyengar 1995], and poll studies [Kull, Ramsey, and

Lewis 2003; Gentzkow and Shapiro 2004]. Our estimates of per-

suasion rates are in the range of most estimates in the literature.

We consider three explanations of our results. The ﬁrst ex-

planation is that the ﬁndings are spurious and are induced by

entry of Fox News in towns that were independently becoming

more conservative. Contrary to this explanation, these towns

were no more conservative, nor were they becoming more conser-

vative before the entry of Fox News. A second explanation is

based on rational learning. To the extent that voters are initially

uncertain about the bias of Fox News, exposure will have a

(temporary) effect on beliefs and voting. Voters attribute the

positive coverage of George W. Bush in 2000 partly to Republican

bias of the media source (Fox News) but partly also to high

quality of the Republican candidate (Bush). By the year 2000,

however, the conservative slant of Fox News should have been

clear. This explanation also makes the prediction that the media

effect should disappear over time, contrary to the evidence that

the Fox News effect does not decrease between 2000 and 2004. A

third explanation is that viewers do not sufﬁciently account for

media bias and are subject to nonrational persuasion. In this

case, exposure to media slant systematically alters beliefs and

voting behavior. In the working paper version [DellaVigna and

Kaplan 2006] we model the latter two explanations.

The latter interpretation relates to behavioral literature on

nonrational persuasion [DeMarzo, Vayanos, and Zwiebel 2003].

Cain, Loewenstein, and Moore [2005] show in an experiment that

evaluators of information do not take sufﬁciently into account the

(known) incentives of the advisors and are thus persuaded by

their advice. Malmendier and Shanthikumar [forthcoming] show

that small investors follow the recommendations of afﬁliated

analysts, despite the conﬂict of interest of the analysts.

Our paper contributes to the evidence on the impact of media

1. Dyck and Zingales [2003] and Huberman and Regev [2001], among others,

ﬁnd that media coverage has a large impact on stock returns, even when arguably

it conveys no new information.

1190 QUARTERLY JOURNAL OF ECONOMICS

market expansions on voter turnout. Expansions of The New York

Times in the 1990s [George and Waldfogel 2006], of television

between 1940 and 1972 [Gentzkow 2006], and of cable in the

1970s [Prior 2006] decrease turnout, while radio entry between

1920 and 1940 increases turnout [Stromberg 2004]. Unlike in

these studies, we examine the introduction of a politically slanted

media and estimate the effect of media persuasion.

The paper also adds to the empirical literature on media bias

[Herman and Chomsky 1998; Hamilton 2004; Puglisi 2004;

Groseclose and Milyo 2005] and the theoretical literature on it

[Mullainathan and Shleifer 2005; Gentzkow and Shapiro 2006].

We provide evidence that exposure to media bias persuades vot-

ers, an implicit assumption underlying most of these papers.

The remainder of the paper is structured as follows. In Sec-

tion II we provide background information on Fox News and we

describe the data. In Section III we present the empirical results,

including a comparison to results from an earlier draft of this

paper in which we found no effect of Fox News. In Section IV we

present estimates of persuasion rates and interpretations, and in

Section V we conclude.

II. FOX NEWS HISTORY AND DATA

Fox News History and Content. In March of 1996, Rupert

Murdoch announced the introduction of a twenty-four-hour-a-

day cable news channel, Fox News. Prior to the launch of Fox

News, news broadcasts took up a small share of programming

of the Fox Broadcasting Corporation, which included channels

like Fox Entertainment and the Fox Family Channel. There

was no national news broadcast, and prime time programming

on the Fox channels did not include news.

The political coverage of Fox News is to the right of the

coverage of the other main television news sources, the major

networks—ABC, CBS, and NCB—and CNN. Groseclose and Mi-

lyo [2005], for example, compute an index of political orientation

of news programs using citations of think tanks. They estimate

that Fox News Special Report is signiﬁcantly to the right of the

other mainstream television media (ABC, CBS, CNN, and NBC).

The news coverage of Fox News is also estimated to be to the right

of the average U. S. elected ofﬁcial.

The distribution of Fox News started on October 7, 1996, in a

1191THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

limited number of cable markets. The cable industry is a local

natural monopoly due to the ﬁxed cost of laying cables. In our

sample, only 10 percent of towns have two or more cable compa-

nies. In addition, cable companies face a technological constraint

on the number of channels. News channels like Fox News have to

convince local cable companies to be added, often at the expense

of other channels. The timing of the agreement between Fox

News and the cable companies is one factor inducing idiosyncratic

diffusion of Fox News. TCI was one of the ﬁrst companies to sign

an agreement. By November 2000, AT&T Broadband, which ac-

quired TCI Cable in 1999, offered Fox News in 32.5 percent of the

1,955 towns served by its afﬁliates (in our sample of twenty-eight

U. S. states). Adelphia Communications, which had a late agree-

ment with Fox News, offered Fox News in only 7.5 percent of the

1,592 towns in our sample served by its afﬁliates.

In addition to the twenty-four-hour cable programming, Fox

News distributes short news segments to local TV stations that

are afﬁliates of Fox Broadcasting. However, the twenty-four-hour

channel is only available via cable and to twelve million satellite

subscribers (in 2000).

By the year 2000, Fox News was present in 20 percent of

towns in our sample with cable service. Since the towns reached

by Fox News in 2000 were more than twice as large as the

remaining towns, Fox News was available to 34.3 percent of the

population of these states.

Fox News Audience. We document the Fox News penetration

and the composition of the Fox News audience using microlevel

data from Scarborough Research. Scarborough uses a represen-

tative panel of households to collect demographic variables and

two audience measures for each TV channel surveyed. The ﬁrst

and more inclusive audience measure, the recall measure, is the

share of respondents who answer yes to the question on whether

they watched a given channel in the past seven days. The second

and more restrictive measure, the diary measure, is tabulated

from a week-long diary of TV watching and is the share of re-

spondents who watched a channel for at least one full half-an-

hour block according to the seven-day diary.

2. As of June 2000, 14,458,000 U. S. households subscribed to a satellite

service, but two million of these subscribers did not receive Fox News (Satellite

Broadcasting and Communications Association, from http://www.sbca.com/

index.asp).

1192 QUARTERLY JOURNAL OF ECONOMICS

In column (1) of Table I, we report summary statistics for the

105,201 respondents to the August 2000 –March 2001 survey. The

recall audience for Fox News is 17.3 percent, and 34.1 percent for

CNN. According to this measure, by the year 2000, Fox News

already had an audience half as large as that of CNN. The diary

audience is not available for this sample. We also present sum-

mary statistics for the Fox News audience (column (2)) and for the

rest of the sample (column (3)). The education level and unem-

ployment rate are comparable across the two samples, African

Americans are somewhat more likely to listen regularly to Fox

News, and Hispanics somewhat less likely. The Fox News audi-

ence is older and more likely to be male.

Turning to the political variables, 37.5 percent of the Fox

News recall audience self-identify as Republican, 29.4 percent as

Democrat, and the remainder as Independent. Among the non-

Fox News audience, 26.2 percent identify as Republican and 32.4

percent as Democrat. Fox News viewers therefore are more likely

to be Republican.

Since the audience data are from 2000, after

the entry of Fox News, this difference could be due either to

sorting to Republicans into the Fox News audience or to a per-

suasion effect of exposure to Fox News. Self-reported turnout to

Presidential elections is higher in the Fox News audience.

In columns (4)–(6), we focus on the subsample for which zip code

of residence and the diary audience measure are both available. This

sample was recorded between February 2000 and August 2001 in

ﬁve geographical areas.

We further restrict the sample to the

11,388 respondents living in one of the 568 towns with available

cable and election data. In Section IV.A, we use this subsample to

estimate the impact of Fox News availability via cable on the Fox

News audience. This sample (column (4)) is similar to the whole

sample (column (1)) both with respect to the measure of the Fox

News recall audience and with respect to demographics, except for a

higher share of Hispanic viewers. The diary audience is three to ﬁve

times smaller than the corresponding recall audience: 0.035 for Fox

News (recall audience 0.166) and 0.103 for CNN (recall audience

0.353). The diary audience measure is less inclusive than the recall

3. We ﬁnd a similar pattern for audience measures of CNN and CNBC,

suggesting that the selection of Republicans into the Fox News audience may

simply reﬂect selection of Republicans into news channels.

4. The data include respondents residing in the Designated Market Areas

(DMAs) of Chicago (September 2000 –August 2001), Los Angeles (February 2000–

January 2001), Pittsburgh (September 2000 –August 2001), New York (March

2000–February 2001), and Washington, D.C. (March 2000 –February 2001).

1193THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

TABLE I

SUMMARY STATISTICS ON FOX NEWS AUDIENCE (SCARBOROUGH DATA)

Sample

Summary statistics

All survey respondents Matched zip-coded subsample

All

Fox News

recall audience

Fox News

non-audience All

Fox News

diary audience

Fox News

non-audience

(1) (2) (3) (4) (5) (6)

Cable variables

Fox News 0.173 1 0 0.166* 0.591* 0.146*

(recall audience) (0.379) (0.372) (0.493) (0.353)

Fox News 0.035 1 0

(diary audience) (0.185)

CNN 0.341 0.619 0.283 0.353* 0.603* 0.341*

(recall audience) (0.474) (0.486) (0.451) (0.478) (0.490) (0.474)

CNN 0.103 0.350 0.094

(diary audience) (0.304) (0.478) (0.292)

Demographic variables

Some college 0.214 0.219 0.213 0.215 0.206 0.215

(0.410) (0.414) (0.410) (0.411) (0.405) (0.411)

College graduate 0.344 0.356 0.341 0.386 0.452 0.384

(0.475) (0.479) (0.474) (0.487) (0.498) (0.486)

African American 0.097 0.111 0.094 0.084 0.020 0.086

(0.296) (0.314) (0.292) (0.277) (0.140) (0.281)

Hispanic 0.107 0.081 0.112 0.180 0.094 0.183

(0.309) (0.273) (0.315) (0.384) (0.293) (0.387)

Unemployment 0.022 0.018 0.023 0.023 0.005 0.024

(0.147) (0.134) (0.149) (0.151) (0.070) (0.153)

1194 QUARTERLY JOURNAL OF ECONOMICS

TABLE I

(CONTINUED)

Sample

Summary statistics

All survey respondents Matched zip-coded subsample

All

Fox News

recall audience

Fox News

non-audience All

Fox News

diary audience

Fox News

non-audience

(1) (2) (3) (4) (5) (6)

Age 45.679 49.744 44.827 44.506 51.727 44.241

(16.633) (16.995) (16.429) (16.443) (16.362) (16.386)

Male 0.424 0.481 0.412 0.427 0.526 0.423

(0.494) (0.500) (0.492) (0.495) (0.500) (0.494)

Political variables

Republican 0.282 0.375 0.262 0.267 0.536 0.257

(0.450) (0.484) (0.440) (0.442) (0.499) (0.437)

Democrat 0.319 0.294 0.324 0.335 0.159 0.342

(0.466) (0.455) (0.468) (0.472) (0.366) (0.474)

Voter turnout 0.693 0.769 0.677 0.677 0.819 0.672

(0.461) (0.421) (0.468) (0.468) (0.386) (0.470)

Subscriptions

Cable 0.687 0.784 0.666 0.754 0.886 0.749

(0.464) (0.411) (0.471) (0.431) (0.318) (0.434)

Satellite 0.147 0.138 0.149 0.104 0.122 0.103

(0.354) (0.344) (0.356) (0.305) (0.327) (0.304)

No. observations N ⫽ 105,201 N ⫽ 18,223 N ⫽ 86,968 N ⫽ 11,388 N ⫽ 403 N ⫽ 10,985

Notes: Data from Scarborough Research. Columns (1) through (3) show mean and standard deviation of variables in the whole U. S. sample (August 2000 –March 2001, column (1)) and

in the subsamples of regular Fox News audience (column (2)) and nonregular Fox News audience (column (3)). Columns (4) through (6) show mean and standard deviation of variables in

the subsample with zip code data that matches to a town in the cable and election sample (February 2000–August 2001, column (4)) and in the subsamples of diary Fox News audience

(column (5)) and nondiary Fox News audience (column (6)). The recall Fox News audience is an indicator variable for respondents who stated that they watched a channel in the past seven

days. The diary Fox News audience is an indicator variable for whether the respondent watched at least a full thirty-minute block of Fox News in the survey week.

* The number of observations for Fox News (regular audience) is 5,070 in column (4), 237 in column (5), and 5,307 in column (6). Same number of observations for CNN (regular

audience).

1195THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

measure, since it excludes anyone who, in the previous week,

watched a channel for less than a full half hour block (a likely

pattern for a news channel). It is also less subject to memory biases,

which may lead to over-reporting of the recall audience. Throughout

the paper, we report the results with both measures.

In columns (5) and (6) we compare the Fox News audience

and the non-Fox News audience according to the diary measure.

The differences between these two samples resemble the ones

found according to the recall audience measures (columns (2) and

(3)), except that political differences are more accentuated and

that African Americans are less likely to watch Fox News accord-

ing to the diary measure.

Data. The data on local cable companies are from a paper

copy of the Television and Cable Factbook, 2001 edition [Warren

2001]. This edition contains information as of November 2000,

that is, right up to the 2000 elections. We did not collect infor-

mation for the year 1996 since Fox News became available only in

October 1996 and just for a limited number of markets. In the

Appendix we present details on this data.

The main source of election data was the Election Division of

the Secretary of State of each state. Other sources are the Federal

Election Project [Lublin and Voss 2001] for the year 2000, the

Record of American Democracy (ROAD) Project [King et al. 1997]

for the year 1988, and the Atlas Election data [Leip 2004] for the

2004 presidential election.

We aggregate the voting information to the town level. A ﬁrst

group of states—California, New Jersey, New York, and the New

England States— directly provide voting information at the town

level, which we employ. A second group of states—Iowa, Minne-

sota, Michigan, Montana, Ohio, Pennsylvania, Wisconsin, and

Wyoming—provide precinct-level voting information with corre-

sponding town name, which we use to aggregate to the town level.

A third group of states—Alaska, Alabama, Arkansas, Hawaii,

Idaho, Missouri, North Dakota, South Carolina, Tennessee, Utah,

and Virginia— only have precinct-level voting information, with

precinct names that usually include the name of the town but

sometimes do not. Examples of precinct names are “02—Concord

Elem School” and “Hot Springs Retirement Hm.” For these states,

we recover the town name from the precinct name by elimination

of numbers and commonly used words, such as “School” and

1196

QUARTERLY JOURNAL OF ECONOMICS

“Retirement Hm.”

We then aggregate the voting data over pre-

cincts with the same town name in a given county and state. The

twenty-eight U. S. states that have voting information that we

can aggregate to the town level for both years 1996 and 2000 form

the sample used in this paper. The aggregation procedure gener-

ates 26,710 distinct localities.

For the twenty-eight U. S. states in our sample, we collect

demographics from the 2000 and the 1990 Census at the level of

“Place,” including “Remainders of Place.” We transform the place

name and aggregate the Census data using the same code employed

for the election and cable data. This procedure leaves 27,064 towns

with information from both the 2000 and the 1990 Census.

We match the cable, the election, and the Census data by the

state, county, and town name, yielding 10,126 localities. We drop

289 towns with multiple cable systems, at least one of which

carries Fox News and at least one of which does not. For these

towns, we do not know if cable consumers have access to Fox

News. Additionally, we drop 324 towns with cable systems that do

not offer CNN as part of the cable package. In these towns, cable

offerings are typically limited to the reprogramming of local cable

channels. Their news programming, therefore, is not comparable

to the programming of the other towns.

Finally, we drop 257

towns with likely voting data problems: 238 towns for which the

number of precincts generating the town-level vote count differs

by more than 20 percent between 1996 and 2000;

and nineteen

towns for which the total number of votes cast in the presidential

election differs by more than 100 percent between 1996 and 2000.

For these observations, the problems are likely due to imperfect

matching of the precincts aggregated to the town level in 1996

and 2000.

The ﬁnal sample of 9,256 towns has comparable Fox News

availability relative to the initial sample and somewhat lower

Republican vote share in 2000 and 1996 because the unmatched

towns are more likely to be small and rural. The ﬁnal sample

5. The Stata ado ﬁle that translates precinct names into town names is

available upon request.

6. The results do not vary if we include these towns.

7. We do not apply this criterion for Michigan, New Hampshire, New York,

Ohio, Rhode Island, and Utah since the numbering of precincts is not comparable

across 1996 and 2000.

1197THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

TABLE II

SUMMARY STATISTICS ON CABLE AND ELECTION DATA

All sample Mixed districts Mixed counties

All towns

Fox News

in 2000

No Fox in

2000

Fox News

in 2000

No Fox in

2000

Fox News

in 2000

No Fox in

2000

(1) (2) (3) (4) (5) (6) (7)

Cable variables

Number of channels 28.60 44.52 24.73 44.39 24.41 45.00 26.05

(14.64) (15.98) (11.31) (16.14) (11.57) (16.06) (11.81)

Potential subscribers 78,124 163,622 57,384 140,457 47,373 167,006 70,832

(149,015) (246,661) (103,131) (198,871) (91,025) (254,926) (116,337)

Voting variables

Rep. vote share in 1996 0.470 0.479 0.467 0.482 0.475 0.477 0.475

(0.125) (0.125) (0.125) (0.124) (0.124) (0.125) (0.127)

Rep. vote share in 2000 0.538 0.538 0.538 0.541 0.550 0.533 0.536

(0.130) (0.129) (0.130) (0.128) (0.126) (0.129) (0.133)

Log turnout in 1996 ⫺0.583 ⫺0.583 ⫺0.583 ⫺0.583 ⫺0.578 ⫺0.573 ⫺0.566

(0.481) (0.482) (0.480) (0.471) (0.732) (0.434) (0.418)

Log turnout in 2000 ⫺0.522 ⫺0.525 ⫺0.521 ⫺0.525 ⫺0.518 ⫺0.510 ⫺0.504

(0.491) (0.497) (0.490) (0.487) (0.483) (0.449) (0.431)

Census variables for 2000

Population 9,612 11,516 9,150 10,564 7,157 11,872 12,266

(32,661) (32,427) (32,703) (31,000) (23,261) (33,678) (37,678)

Some college 0.257 0.259 0.257 0.258 0.257 0.258 0.254

(0.064) (0.063) (0.064) (0.064) (0.066) (0.063) (0.067)

College 0.195 0.220 0.189 0.216 0.178 0.224 0.210

(0.133) (0.147) (0.129) (0.145) (0.118) (0.150) (0.146)

African American 0.033 0.031 0.034 0.028 0.027 0.030 0.026

(0.095) (0.082) (0.098) (0.073) (0.083) (0.084) (0.072)

Hispanic 0.031 0.035 0.030 0.032 0.027 0.035 0.041

(0.073) (0.072) (0.073) (0.067) (0.065) (0.074) (0.096)

Unemployed 0.051 0.051 0.052 0.051 0.052 0.050 0.053

(0.035) (0.035) (0.035) (0.035) (0.035) (0.036) (0.038)

1198 QUARTERLY JOURNAL OF ECONOMICS

TABLE II

(CONTINUED)

All sample Mixed districts Mixed counties

All towns

Fox News

in 2000

No Fox in

2000

Fox News

in 2000

No Fox in

2000

Fox News

in 2000

No Fox in

2000

(1) (2) (3) (4) (5) (6) (7)

Urban 0.406 0.537 0.374 0.518 0.331 0.556 0.441

(0.438) (0.447) (0.429) (0.446) (0.416) (0.446) (0.447)

Census variables, change from 1990 to 2000:

Population 704 772 687 681 584 805 934

(3,457) (3,775) (3,375) (3,499) (2,727) (3,974) (4,461)

Some college 0.040 0.035 0.041 0.036 0.044 0.035 0.034

(0.048) (0.046) (0.049) (0.046) (0.049) (0.046) (0.047)

College 0.037 0.041 0.036 0.041 0.035 0.042 0.041

(0.042) (0.044) (0.042) (0.045) (0.041) (0.045) (0.043)

African American 0.004 0.003 0.004 0.003 0.003 0.003 0.004

(0.026) (0.025) (0.026) (0.024) (0.024) (0.024) (0.024)

Hispanic 0.011 0.013 0.010 0.012 0.010 0.013 0.011

(0.026) (0.030) (0.025) (0.027) (0.025) (0.029) (0.028)

Unemployed ⫺0.012 ⫺0.011 ⫺0.013 ⫺0.011 ⫺0.013 ⫺0.012 ⫺0.012

(0.038) (0.037) (0.039) (0.037) (0.040) (0.038) (0.036)

Urban 0.082 0.079 0.083 0.082 0.080 0.084 0.086

(0.238) (0.239) (0.238) (0.241) (0.240) (0.247) (0.242)

No. of observations N ⫽ 9,256 N ⫽ 1,807 N ⫽ 7,449 N ⫽ 1,734 N ⫽ 5,897 N ⫽ 1,548 N ⫽ 2,342

Notes: Standard deviations in parentheses. The subset “Fox News in 2000” is formed by the towns with availability of Fox News in 2000 in the cable package. The subset “No

Fox in 2000” is the complementary groups of towns. Towns with district variation are towns in districts in which there is at least one town that does not get Fox News and one town

that does. Towns with county variation are similarly deﬁned except at the county level. Potential subscribers is deﬁned as the total voting-age population of the towns reached by

a cable provider. Republican two-party vote share is the votes received by the Republican candidate in the presidential election divided by the votes received by both the Republican

and Democratic candidates. Log turnout is measured by the log of the ratio of total votes cast in a given town and year to the voting-age population of the town in the same year.

The voting-age population data for 1996 is interpolated from the 1990 and 2000 Census. The full list of Census variables is presented in Appendix II. Observations unweighted.

1199THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

covers 65.9 percent of the population and 68.6 percent of total

votes cast for the twenty-eight states in the year 2000.

Summary Statistics. Table II presents unweighted summary

statistics on the cable and election data. The average cable sys-

tem in the year 2000 included twenty-eight channels in the Basic

and Expanded Basic programming and reached a population of

78,124. The mean town population was 9,612 with a median of

2,766. As Census controls, we include the share of the population

with some college, the share of college graduates, the share of

African Americans and of Hispanics, the unemployment rate, and

the share of the town that is urban (shown in Table II). We also

include the share of high school graduates, the share of males, the

marriage rate, the employment rate, and average income (not

shown in Table II).

We compare towns that offered Fox News in their program-

ming (column (2)) and towns that did not (column (3)). Towns that

offer Fox News have a substantially higher number of channels

offered (44.5 versus 24.7), are 25 percent larger, are served by

cable companies that reach three times as many people, and are

more likely to be urban.

More importantly, towns that offered Fox News by 2000

increased their Republican vote share by 5.9 percentage points

(from 47.9 to 53.8 percent) between 1996 and 2000, while those

that did not offer Fox News increased theirs by an even larger 7.1

percentage points (from 46.7 to 53.8 percent). These ﬁgures sug-

gest a perverse Fox News effect. This result, however, does not

weight towns by size, nor does it take into account differences

between Fox and non-Fox towns in voting trends across geo-

graphical areas, demographic composition, and cable market.

Later, we estimate the Fox News effect, taking into account all

these factors.

The overall sample spans 235 congressional districts, out of

435 total. Out of these 235 districts, 152 districts include both

8. The coverage rate is lower than 100 percent for three reasons: (i) we drop

some of the largest cities like New York, which have several cable systems, some

of which carry Fox News, and some of which do not; (ii) in states like Missouri,

some counties have numeric precinct names that we cannot match to a town; and

(iii) in states like Arkansas, complicated precinct names induce a poor match

between the election data and the cable and Census data. The exclusion of large

cities or certain counties or precincts should not affect the results, as long as Fox

News availability and the election outcomes are measured correctly for the match-

ing towns. Details on the state-by-state coverage rate is in Appendix Table I in

DellaVigna and Kaplan [2006].

1200 QUARTERLY JOURNAL OF ECONOMICS

towns that offered Fox News and towns that did not. In our

difference-in-difference speciﬁcation with district ﬁxed effects,

the effect of Fox News is estimated on the 7,631 towns in this

subsample. Towns in this subsample (columns (4) and (5) of Table

II) are smaller but otherwise comparable to the overall sample.

We also consider the distribution of Fox News at the ﬁner

geographical level of the county. Only 284 counties out of 1,156

incorporate both towns with Fox News and towns without (Figure

I). In our speciﬁcation with county ﬁxed effects, the effect of Fox

News is estimated on the 3,890 towns in these counties. Towns

with Fox News (column (6) of Table II) and without Fox News

(column (7)) in this subsample are close geographical neighbors

and, therefore, more closely matched on observables.

III. EMPIRICAL RESULTS

III.A. Selection

In this paper, we compare towns with Fox News in their

programming in the year 2000 to towns without Fox News. Since

the assignment of towns into these two groups is not random, we

investigate the nature of the selection and estimate which town-

level variables predict the availability of Fox News in 2000. In

particular, we focus on political variables. Fox News may well

have expanded ﬁrst in Republican areas since demand for its

services is likely to be higher in these areas. If Republican areas

were becoming more Republican between 1996 and 2000, the

estimated Fox News effect may just be capturing political trends.

The Fox News variable, d

k,2000

FOX

, equals one if all cable sys-

tems in town k in year 2000 include Fox News in either the Basic

package or one of the Expanded Basic packages, and zero if no

cable system includes Fox News. We estimate a linear probability

model

(1) d

k,2000

FOX

⫽ ␣ ⫹ ␤v

k,1996

R,Pres

⫹ ␤

k,1996

Pres⬘

⫹ ⌫

2000

k,2000

⫹ ⌫

00–90

k,00–90

⫹ ⌫

k,2000

⫹ ε

The pre-Fox News political variables from the 1996 presidential

elections are the two-party Republican vote share, v

k,1996

R,Pres

, and

the voter turnout measured by log of votes cast as share of

population, t

k,1996

Pres⬘

. The demographic variables are X

k,2000

, the

9. The results are similar with logit and conditional logit speciﬁcations.

1201THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

FIGURE I

Fox News Availability by County, 2000

Note: Proportion for each county is calculated as the ratio of number of towns with Fox News available via cable to total number of

towns in the county. Alaska and Hawaii are also in the data set but are not included on the map due to space constraints.

1202 QUARTERLY JOURNAL OF ECONOMICS

set of controls from the 2000 Census, and X

k,2000–1990

, the set of

changes in controls between the 1990 Census and the 2000 Cen-

sus (see Table II). Finally, the controls for features of the cable

system are C

k,2000

, deciles in the number of channels provided

and in the number of potential subscribers. To ensure that the

results are representative of the average voter, and since the

precision of the vote share variable v

k,1996

R,Pres

is increasing in the

number of votes cast, we weight the observations by votes cast in

1996.

The standard errors are clustered at the level of the 2,992

local cable companies.

We ﬁrst estimate (1) without controls (column (1) of Table

III). Unconditionally, Fox News availability is signiﬁcantly posi-

tively correlated with town turnout, but not with Republican vote

share. As we add demographic controls (column (2)), the latter

result changes. Fox News availability in 2000 is substantially

higher in more Republican towns: a 10 percentage point increase

in Republican vote share is associated with a 6.36 percentage

point increase in the likelihood of Fox News availability. Since

Fox News is more likely to enter into urban towns, and these

towns are less likely to be Republican, adding demographics

variables in column (2) raises the coefﬁcient on Republican vote

share. Next, we add the controls C

k,2000

for cable system features

(column (3)), raising the R

to 0.4093; larger cable systems are much

more likely to offer Fox News. Controlling for cable system features

lowers the coefﬁcient ␤

on the Republican vote share by half.

In column (4), we add congressional district ﬁxed effects.

With these additional geographic controls, speciﬁcation (1) cap-

tures the determinants of within-district Fox News availability,

conditional on demographic and cable controls. (The coefﬁcients

on the controls are reported in Appendix II). In this speciﬁcation,

there is no evidence that towns with higher Republican vote

share are more likely to offer Fox News; in fact, the estimated ␤

⫽

⫺.0343 is negative, albeit insigniﬁcant. Similarly, the turnout

coefﬁcient is small and insigniﬁcant. Given the precision of the

estimates, we can reject substantial effects of pre-existing politi-

cal composition on the availability of Fox News, conditional on the

control variables. Moreover, we cannot reject the joint test that

the twenty-four demographic controls are zero (F-test ⫽ 1.11).

Once we control for geographic heterogeneity and size of the cable

10. The results are similar if we weight by votes cast in 2000 or by

population.

1203THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

TABLE III

DETERMINANTS OF FOX NEWS AVAILABILITY,LINEAR PROBABILITY MODEL

Dep. var.

Availability of Fox News via cable in 2000

(1) (2) (3) (4) (5) (6) (7)

Pres. republican vote share in

1996

0.1436 0.6363 0.3902 ⫺0.0343 ⫺0.0442 0.0902 0.0627

(0.1549) (0.2101)*** (0.1566)** (0.0937) (0.1024) (0.1321) (0.1333)

Pres. log turnout in 1996 0.1101 0.0909 0.0656 0.0139 ⫺0.0053 0.0286 0.0257

(0.0557)** (0.0348)*** (0.0278)** (0.0124) (0.0173) (0.0234) (0.0258)

Pres. Rep. vote share change

1998–1992

0.214 ⫺0.2548

(0.2481) (0.2345)

Control variables

Census controls: 1990 and 2000 — X X X X X X

Cable system controls — — X X X X X

U. S. House district ﬁxed

effects

—— — X — X —

County ﬁxed effects — — — — X — X

F-test: Census controls ⫽ 0 F ⫽ 3.54*** F ⫽ 2.73*** F ⫽ 1.11 F ⫽ 1.28 F ⫽ 1.57** F ⫽ 1.31

F-test: Cable controls ⫽ 0 F ⫽ 18.08*** F ⫽ 21.09*** F ⫽ 18.61*** F ⫽ 8.19*** F ⫽ 8.75***

0.0281 0.0902 0.4093 0.6698 0.7683 0.6313 0.7622

NN⫽ 9,256 N ⫽ 9,256 N ⫽ 9,256 N ⫽ 9,256 N ⫽ 9,256 N ⫽ 3,722 N ⫽ 3,722

Notes: An observation in the linear probability model is a town in one of the twenty-eight U. S. states in the sample. The dependent variable is a binary variable that equals one

if Fox News was part of the town’s local cable package in 2000. The log turnout measure is the log of the ratio of total votes cast in 1996 to voting-age population in the town in 1996.

The population data for 1996 is interpolated from the 1990 and 2000 Census. The census controls are twelve demographic variables from the Census, present both in the 2000 values

and in differences between 2000 and 1990. The Cable System Controls are deciles in the number of channels provided and in the number of potential subscribers. All controls are

listed in Appendix II. The F-test is a joint test of the hypothesis that the Census controls from 1990 and 2000 (respectively, the cable controls) are jointly equal to zero. Robust standard

errors clustered by local cable company in parentheses. The observations are weighted by total votes cast in 1996 presidential election.

* signiﬁcant at 10 percent; ** signiﬁcant at 5 percent; *** signiﬁcant at 1 percent.

1204 QUARTERLY JOURNAL OF ECONOMICS

system, availability of Fox News in 2000 is therefore uncorrelated

with both political outcomes and demographics. We obtain similar

results when we introduce county ﬁxed effects instead of congres-

sional district ﬁxed effects (column (5)). Our interpretation of

these results is that, while overall the availability of Fox News is

highly selective—Fox News enters into larger markets and, given

town size, into more Republican areas—conditional on cable mar-

ket size, the assignment to towns within an area (county or

congressional district) is essentially random.

In columns (6) and (7), we test whether voting trends be-

tween 1988 and 1992 predict the availability of Fox News. Since

town-level data for 1992 is hard to ﬁnd, this reduces the sample

to 3,722 towns. The vote share change in presidential elections

between 1988 and 1992 is not signiﬁcant and switches sign be-

tween the two speciﬁcations.

Overall, Fox News in 2000 selected primarily into cable sys-

tem with a large number of channels, as well as into speciﬁc

counties and districts. Within counties and districts, however,

once we control for features of the cable system, the availability of

Fox News in 2000 appears largely idiosyncratic: the towns which

got Fox News between 1996 and 2000 are no different in the

demographics, the political orientation, or the prior political

trends than the towns that did not get Fox News before 2000. We

exploit this conditional random assignment to study the impact of

Fox News on voting.

III.B. Presidential Elections

We compare towns where Fox News entered the cable market

by the year 2000 (d

k,2000

FOX

⫽ 1) with towns where Fox News was

not available by the year 2000 (d

k,2000

FOX

⫽ 0). We consider the

impact of the entry of Fox News on the change in the Republican

vote share between 1996 and 2000. This strategy exploits the

timing of the entry of Fox News. By the November 1996 elections

Fox News had been launched in only a few markets and, even in

those markets, just one month before the elections. By the No-

vember 2000 elections, Fox News had an audience that was

smaller, but nonetheless comparable to that of CNN. Our base-

line speciﬁcation is

(2) v

k,2000

R,Pres

⫺ v

k,1996

R,Pres

⫽ ␣ ⫹ ␤

k,2000

FOX

⫹ ⌫

2000

k,2000

⫹ ⌫

00–90

k,00–90

⫹ ⌫

k,2000

⫹ ε

1205

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

As in Table III, we control for town-level demographics in levels

k,2000

) and changes (X

k,00–90

) and for cable variables (C

k,2000

The observation are weighted by the votes cast in 1996, and the

standard errors are clustered at the level of the local cable

company.

We ﬁrst implement a simple difference-in-difference estima-

tor and estimate (2) without controls (⌫

2000

⫽⌫

00–90

⫽ 0 and ⌫

⫽

0) (column (1) in Table IV). On average, in our sample the vote

share for Republicans increased by 3.47 percentage points (␣ˆ ⫽

0.0347) between the 1996 and the 2000 elections. Compared to

this overall increase, towns with Fox News became (insigniﬁ-

cantly) less Republican by two-tenths of a percentage point (␤

⫽

⫺.0025) relative to towns without Fox News. The standard error

(0.0037), however, is sufﬁciently large that we cannot rule out

that the entry of Fox News increased the Republican vote share

by half a percentage point. In column (2), we add demographic

controls, raising the R

of the regression from 0.0007 to 0.5207.

The estimate for ␤

, ␤

⫽ 0.0027, becomes positive but is still

insigniﬁcant. In column (3), we add controls for cable size C

k,2000

rendering the Fox News coefﬁcient positive and signiﬁcant (␤

⫽

0.008). Introducing control variables increases the point esti-

mate of ␤

, suggesting that the unobservables bias the estimate

of the Fox News effect downward.

In the two benchmark speciﬁcations we include district ﬁxed

effects (column (4)) and county ﬁxed effects (column (5)) in addi-

tion to the full set of controls. (The coefﬁcients on the controls for

the speciﬁcation in column (4) are reported in Appendix II.) These

speciﬁcations control for unobserved trends in voting that are

common to a geographic area, and that may be correlated with

Fox News availability. The identiﬁcation of ␤

depends on the

comparison of neighboring towns with and without Fox News.

The key advantage of speciﬁcations with cable, demographic, and

geographic controls is that, conditional on these variables, the

availability of Fox News is uncorrelated with political variables

(Table III). The estimate of the effect of Fox News is positive and

signiﬁcant in both cases, 0.0042 and 0.0069, respectively. These

point estimates are substantially more precise than in column (1).

In the speciﬁcations that best control for heterogeneity, availabil-

ity of Fox News increases the Republican vote share by four- to

seven-tenths of a percentage point, a sizeable and precisely esti-

mated effect.

In columns (6) and (7), we replicate the benchmark results

1206 QUARTERLY JOURNAL OF ECONOMICS

TABLE IV

THE EFFECT OF FOX NEWS ON THE 2000 –1996 PRESIDENTIAL VOTE SHARE CHANGE

Dep. var.

Republican two-party vote share change between 2000 and 1996 pres. elections

(1) (2) (3) (4) (5) (6) (7)

Availability of Fox News via

cable in 2000

⫺0.0025 0.0027 0.008 0.0042 0.0069 0.0037 0.0048

(0.0037) (0.0024) (0.0026)*** (0.0015)*** (0.0014)*** (0.0021)* (0.0019)**

Pres. Rep. vote share change

1988–1992

0.0229 0.0514

(0.0216) (0.0219)**

Constant 0.0347 ⫺0.028 ⫺0.0255 0.0116 0.0253 ⫺0.0377 0.0081

(0.0017)*** (0.0245) (0.0236) (0.0154) (0.0185) (0.0258) (0.0313)

Control variables

Census controls: 1990 and 2000 — X X X X X X

Cable system controls — — X X X X X

U. S. House district ﬁxed

effects

—— —X—X—

County ﬁxed effects — — — — X — X

0.0007 0.5207 0.5573 0.7533 0.8119 0.7528 0.8244

NN⫽ 9,256 N ⫽ 9,256 N ⫽ 9,256 N ⫽ 9,256 N ⫽ 9,256 N ⫽ 3,722 N ⫽ 3,722

Notes: An observation in the OLS regression is a town in one of the twenty-eight U. S. states in the sample. The dependent variable is the two-party Republican vote share for

the 2000 presidential election minus the two-party republican vote share for the 1996 presidential election. The variable “Availability of Fox News via cable in 2000” is a binary

variable that equals one if Fox News was part of the town’s local cable package in 2000. The census controls are twelve demographic variables from the Census, present both in the

2000 values and in differences between 2000 and 1990. The cable system controls are deciles in the number of channels provided and in the number of potential subscribers. All

controls are listed in Appendix II. Robust standard errors clustered by local cable company in parentheses. The observations are weighted by total votes cast in the 1996 presidential

election.

* Signiﬁcant at 10 percent; ** signiﬁcant at 5 percent; *** signiﬁcant at 1 percent.

1207THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

after adding the change in the Republican vote share between

1988 and 1992 as an additional control. Over this substantially

smaller sample (3,722 observations), the effect of Fox News avail-

ability is less precisely estimated and somewhat smaller but still

signiﬁcant in the speciﬁcation with county ﬁxed effects.

Since

previous voting trends are not substantial predictors of current

voting trends, and since including them would lower the sample

size substantially, we omit them in the remaining regressions.

Robustness. In Table V, we examine the robustness of the

results to alternative ways of coding the dependent variable (the

vote share), alternative ways of coding the independent variable

(the Fox News indicator), and alternative samples and estimation

methods. A more extensive set of robustness checks is in

DellaVigna and Kaplan [2006]. Here and in most of the next

tables we present the results for the speciﬁcations with U. S.

House District ﬁxed effects; the results are similar for the speci-

ﬁcations with County ﬁxed effects.

First, the results are robust to controlling for the vote share

in 1996 instead of using the vote share change between 2000 and

1996 (column (1)). The results are also robust to using the all-

party vote share (column (2)), an alternative measure that con-

trols for third-party effects.

Second, we also consider an alternative speciﬁcation of expo-

sure to Fox News, the ratio of the number of Fox News subscrib-

ers to population covered. The results (not shown) are similar to,

though less precise than, our main speciﬁcation, which uses a

simple dummy variable.

Third, we present results using alternative samples and es-

timation methods. In column (3) we show that restricting the

sample to the states with a high proportion of correctly matched

election data

yields, if anything, a higher effect of Fox News

entry. We also show (column (4)) that the largest cities are not

driving the estimates: the results are similar to the benchmark

results when we run an unweighted regression on medium- and

large-sized towns (that is, towns with average turnout in 2000 of

11. The lower point estimates depend on the difference in the sample rather

than on the addition of the voting trend controls; we obtain the same result on this

sample when we do not control for trends.

12. We exclude states in which the election data in the ﬁnal sample cover less

than 50 percent of the total votes cast in the state in either 1996 or 2000. This

eliminates all states in which the town names are obtained from the precinct

names, possibly generating erroneous matches with the cable data.

1208 QUARTERLY JOURNAL OF ECONOMICS

TABLE V

THE FOX NEWS EFFECT:ROBUSTNESS AND PERSISTENCE

Dep. var.

Robustness

Persistence Pres.

Rep. vote share

2004–2000

Pres. Rep. vote share change 2000–1996

Rep. two-party

vote share in 2000

All-party

vote share Two-party vote share

(1) (2) (3) (4) (5) (6)

Availability of Fox News via cable in 2000 0.0041 0.004 0.0048 0.0041 0.0047 0.0021

(0.0016)*** (0.0016)** (0.0016)*** (0.0017)*** (0.0016)*** (0.0020)

Republican vote share in 1996 0.9362

(0.0079)***

Control variables

Census controls: 1990 and 2000 X X X X X X

Cable system controls X X X X X X

U. S. House district ﬁxed effects X X X X X X

Election data with high coverage — — X — — —

Unweighted, turnout ⬎ 2000 — — — X — —

Nearest-neighbor matching, unweighted — — — — X —

0.9824 0.827 0.7556 0.7369 — 0.6281

NN⫽ 9,256 N ⫽ 9,256 N ⫽ 7,758 N ⫽ 3,241 N ⫽ 9,256 N ⫽ 8,605

Notes: An observation in the OLS regression is a town in one of the twenty-eight U. S. states in the sample. In column (1), the dependent variable is the two-party Republican vote share

for the 2000 presidential election. In columns (2)–(5), the dependent variable is the Republican vote share for the 2000 presidential election minus the same variables for the 1996 elections.

In column (2), the Republican vote share is computed using the all-party vote share. In columns (3) through (5) the vote share refers to the two-party vote share. In column (6), the dependent

variable is the two-party Republican vote share for the 2004 presidential election minus the same variables for the 2000 elections. The variable “Availability of Fox News via cable in 2000”

is a binary variable that equals one if Fox News was part of the town’s local cable package in 2000. The Census controls are twelve demographic variables from the Census, present both

in the 2000 values and in differences between 2000 and 1990. The cable system controls are deciles in the number of channels provided and in the number of potential subscribers. All controls

are listed in Appendix II.

The sample “Election data with high coverage” excludes states in which the election data in the ﬁnal sample covers less than 50 percent of the total votes cast in the state in

either 1996 or 2000. The sample “Unweighted, turnout ⬎ 2,000” excludes towns with turnout lower than 2,000 people in the year 2000. The speciﬁcation in column (5) is the estimate

of the average treatment on the treated for nearest-neighbor matching estimator, based on matching on the listed controls; the estimate averages the treatment for the closest four

matches and is bias-corrected (Abadie et al., 2001). Robust standard errors clustered by local cable company in parentheses (except in column (5)). The observations are weighted

total votes cast in the 1996 presidential election except in columns (4) and (5).

* signiﬁcant at 10 percent; ** signiﬁcant at 5 percent; *** signiﬁcant at 1 percent.

1209THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

at least 2,000 votes). In Section III.C, we show that the estimated

effects are instead smaller in small, mostly rural towns.

To check the robustness of our OLS results, we present the

results of a simple matching procedure, nearest-neighbor match-

ing [Abadie et al. 2001]. Each town with Fox News (treatment

town) is matched to the four non-Fox News towns (control towns)

with the closest values of the controls. The match is based on

cable and Census controls and on District indicator variables

(column (5)). The (unweighted) average treatment effect of Fox

News (0.0047) is signiﬁcant and similar to our benchmark ﬁnd-

ings. Finally, the results are also robust to adopting the optimal

trimming approach of Crump et al. [2005], which focuses the

analysis on an optimal subsample in which treatment and control

observations are more comparable (not shown).

Persistence of Effects. We also ﬁnd that the introduction of

Fox News in 2000 is associated with an (insigniﬁcant) 0.2 per-

centage point vote share increase between 2000 and 2004. The

effect of Fox News therefore appears to be persistent, if not

increasing over time. Persistence is consistent with the predic-

tions of a model of nonrational persuasion; however, this result

could also be due to greater audience in Fox News areas over the

2000–2004 period.

Comparison with Earlier Results. We now reconcile the ﬁnd-

ings with our earlier ﬁndings of a null effect of Fox News, as

discussed by Krueger [2005]. In an earlier draft, we presented

unweighted regressions, we did not drop a group of observations

with substantial measurement error, and we used a smaller

sample of twenty-four states. In all three respects, we ﬁnd the

current speciﬁcation preferable. In Appendix III, we introduce in

three successive steps the earlier speciﬁcation and show that,

while each of the factors mattered, the ﬁrst two made the most

difference. The estimates of the Fox News effect are 0.3 percent-

age points lower (0.0014 and 0.0040) if we run unweighted re-

gressions (columns (1) and (2)). The effect is still signiﬁcant with

county ﬁxed effects but not with district ﬁxed effects. The lower

point estimates are likely due to smaller treatment effects in

small, more rural towns (see Section III.C) and possibly to higher

measurement error in very small towns. Regressions weighted by

turnout better represent the impact of Fox News on the average

voter.

In columns (3) and (4), in addition to running unweighted

1210 QUARTERLY JOURNAL OF ECONOMICS

regressions, we also include observations that are likely mea-

sured with substantial error. We include (as treated) 289 towns

where Fox News is offered in parts but not all of the town, and

257 towns with likely voting data problems (see Section II for

details). Consistent with increased measurement error in the Fox

News variable, the estimates of the Fox News effect are 0.2

percentage points lower. Finally, in columns (5) and (6), we ex-

clude the data from the states of Hawaii, North Dakota, New

Jersey, and Wyoming, which we were unable to collect until after

our initial results. Excluding these states has only a small impact

on the estimates. This last speciﬁcation, which detects no impact

of Fox News, is essentially the one that appeared in the earlier

draft.

Magnitudes. Across the different speciﬁcations, the entry of

Fox News into a cable market by the year 2000 had a signiﬁcant

effect on the Republican vote share in presidential elections. The

implied conﬁdence intervals for the benchmark estimates (col-

umns (4) and (5) of Table IV) are (0.0012, 0.0072) with district

ﬁxed effects and (0.0041, 0.0097) with county ﬁxed effects. The

ﬁndings, therefore, are consistent with both a small (but positive)

effect of Fox News and a fairly large effect, close to 1 percentage

point.

How large are these effects relative to shifts in vote share

between 1996 and 2000? The average weighted change in vote

share between 1996 and 2000 in our sample is 3.47 percentage

points, with a standard deviation of 4.02. The estimated impact of

Fox News is one-tenth of a standard deviation with district ﬁxed

effects, and one-sixth of a standard deviation with county ﬁxed

effects. The impact of Fox News is small but not negligible.

As a second measure, we estimate the number of votes that

Fox News is likely to have shifted. We assume a treatment effect

of Fox News of 0.55 percentage points, the midpoint of the bench-

mark estimates, and a diffusion of Fox News of 34 percent of the

population, also for the twenty-two states for which we do not

have data. The estimated impact of Fox News on the Republican

vote share is then 0.34 ⴱ (0.0055) ⫽ 0.0019, that is, 0.19 percent-

age points. Assuming that Fox News did not affect turnout sub-

stantially, Fox News shifted approximately 200,000 votes from

the Democratic candidate to the Republican candidate.

We also predict the number of votes shifted by Fox News in

Florida, the pivotal state in the 2000 U. S. presidential election.

1211THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

In 2000, Fox News reached 32.8 percent of the Florida population.

We assume that the Fox News effect on the 5,963,110 Florida

votes cast is the same as in our sample. Under this assumption,

the introduction of Fox News shifted 0.328 ⴱ (0.0055) ⴱ

5,963,110 ⫽ 10,757 votes, a number substantially larger than

Bush’s ofﬁcial margin of victory of 537 votes.

Overall, while the entry of Fox News had a relatively small

impact on the 2000 election, it may still have contributed to the

Bush victory in the unusually close election. Moreover, this im-

pact may become larger over time as the Fox News audience and

diffusion grows.

III.C. Interactions

In Table VI, we examine how the Fox News effect interacts

with town characteristics, namely the number of channels, the

share of the population that is urban, and the political orientation

of the district. We split congressional districts into thirds by the

2000 Republican vote share.

First, we ﬁnd that the Fox News effect is smaller in towns

with more cable channels: an increase of ten cable channels (0.7

standard deviations) reduces the effect by 0.19 percentage points

with district ﬁxed effects (column (1)) and by 0.13 percentage

points with county ﬁxed effects (column (2)). When the Fox News

message competes with a larger number of channels, its impact

appears diminished [Mullainathan and Shleifer 2005]. The lower

Fox News impact could reﬂect exposure to more balanced report-

ing (though CNN and the network news are available in all towns

in the sample) or merely lower audience rates for Fox News when

more channels are available.

Second, we ﬁnd that the impact of Fox News is (marginally

signiﬁcantly) larger in urban towns and lower in the Republican

districts, signiﬁcantly so with county ﬁxed effects. Both of these

results may be explained by the fact that in rural towns and in

Republican Districts most people already voted Republican, and

therefore, the share of the population at risk of being convinced

was smaller. In addition, we also ﬁnd (not reported) that the Fox

News effect is lower in the South, again potentially reﬂecting a

smaller at-risk population.

III.D. Placebos

We exploit the timing of the Fox News entry to construct

placebo treatments. The ﬁrst placebo treatment (column (3) in

1212 QUARTERLY JOURNAL OF ECONOMICS

TABLE VI

THE FOX NEWS EFFECT:INTERACTIONS AND PLACEBO SPECIFICATIONS

Dep. var.

Interactions Placebo speciﬁcations

Presid. Rep. vote share Presidential Republican vote share

2000–1996 2000–1996 1996–1992 1992–1988

(1) (2) (3) (4) (5)

Availability of Fox News via cable in 2000 0.0109 0.0105 0.0036 ⫺0.0024 0.0026

(0.0042)*** (0.0039)*** (0.0016)** (0.0031) (0.0026)

Availability of Fox News via cable in 2003 ⫺0.0001

(0.0012)

Fox News in 2000* (no. of channels/10) ⫺0.0019 ⫺0.0013

(0.0008)** (0.0008)

Fox News in 2000* (urban in 2000) 0.004 0.0033

(0.0023)* (0.0020)*

Fox News in 2000* (swing district) ⫺0.0043 ⫺0.0004

(0.0030) (0.0023)

Fox News in 2000* (Republican district) ⫺0.0028 ⫺0.0064

(0.0027) (0.0024)***

Control variables:

Census controls: 1990 and 2000 X X X X X

Cable system controls X X X X X

U. S. House district ﬁxed effects X — X X X

County ﬁxed effects — X — — —

0.754 0.8124 0.7523 0.6197 0.6517

NN⫽ 9,256 N ⫽ 9,256 N ⫽ 8,645 N ⫽ 4,006 N ⫽ 3,722

Notes: An observation in the OLS regression is a town in one of the twenty-eight U. S. states in the sample. In columns (1) through (3) the dependent variable is the two-party Republican

vote share for the 2000 presidential elections minus the same variable for the 1996 elections. In column (4) the dependent variable is the same, except that it refers to the change between

1992 and 1996, and in column (5) it refers to the change between 1988 and 1992. The variable “Availability of Fox News via cable in 2000” is a binary variable that equals one if Fox News

was part of the town’s local cable package in 2000, and similarly for the 2003 variable. The Census controls are twelve demographic variables from the Census, present both in the 2000 values

and in differences between 2000 and 1990. The Cable system controls are deciles in the number of channels provided and in the number of potential subscribers. All controls are listed in

Appendix II. In columns (1) and (2) the variables urban, no. of channels, swing district, and Republican district are included in the regressions (coefﬁcients not shown).

The indicator variables “swing district” and “Republican district” are determined dividing the 9,256 observations into thirds based on the two-party Republican vote share in the

2000 presidential elections at the U. S. House District level. The variable “swing district” indicates a district in the middle third (vote share between .49 and .552). The variable

“Republican district” indicates a district in the top third (vote share higher than .552). The omitted category indicates the Democratic districts. Robust standard errors clustered by

local cable company in parentheses. The observations are weighted by total votes cast in the 1996 presidential election.

* signiﬁcant at 10 percent; ** signiﬁcant at 5 percent; *** signiﬁcant at 1 percent.

1213THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

Table VI) uses data on Fox News diffusion in 2003. In 2003, Fox

News was available in 4,844 out of 8,645 towns.

The introduc-

tion of Fox News after the year 2000 should not affect the change

in vote share between 1996 and 2000. Indeed, controlling for Fox

News availability in 2000, Fox News availability in 2003 has no

effect on voting.

In a second set of placebo treatments, we estimate whether

the introduction of Fox News in 2000 predicts the vote share

change between 1992 and 1996 (column (4)) or between 1988 and

1992 (column (5)). Obviously, Fox News introduction in 2000

should not affect voting between years in which Fox News did not

exist. We ﬁnd no evidence of a signiﬁcant correlation in either

time period. Voting trends are unlikely to be responsible for the

Fox News effect.

III.E. Voter Turnout

The signiﬁcant impact of Fox News on the Republican vote

share could occur for two reasons. First, Fox News entry con-

vinced Democratic voters to vote Republican. Second, Fox News

attracted new Republican voters. We use measures of turnout to

test these hypotheses.

The baseline regression for voter turnout is

(3) t

k,2000

Pres

⫺ t

k,1996

Pres

⫽ ␣ ⫹ ␤

k,2000

FOX

⫹ ␥关ln 共Pop

k,2000

兲

⫺ ln 共Pop

k,1996

兲兴 ⫹ ⌫

2000

k,2000

⫹ ⌫

00–90

k,00–90

⫹ ⌫

k,2000

⫹ ε

where t

k,t

Pres

is the log total votes in town k in year t: t

k,t

Pres

⫽

ln (V

k,t

TOT,Pres

). The change in this measure over time is the per-

cent change in total votes cast. This speciﬁcation controls for the

percentage change in the voting-age town population over time,

ln (Pop

k,2000

) ⫺ ln (Pop

k,1996

) since increases in population

would naturally increase the number of votes cast.

Columns (1)–(3) in Table VII show the results. The average

change in log votes is 0.0869, implying an 8.69 percent higher

turnout in the much tighter presidential race of 2000. The esti-

mate for ␤

is positive but insigniﬁcant with district ﬁxed effects

and is large and signiﬁcant with county ﬁxed effects. This second

estimate (␤

⫽ 0.0178) suggests that Fox News increased turn-

out by 1.78 percent, a large effect. In both speciﬁcations, the

13. We exclude 281 towns which offer Fox News in 2003 in one, but not all,

of the cable systems in the town. The data are updated up to the end of 2003.

1214 QUARTERLY JOURNAL OF ECONOMICS

TABLE VII

FOX NEWS AND OTHER POLITICAL OUTCOMES:TURNOUT AND SENATORIAL ELECTIONS

Dep. var.

Turnout (presidential elections) Senatorial elections

Change in log (total votes cast) between

2000 and 1996 pres. elections

Republican vote share in 2000 senatorial

elections

(1) (2) (3) (4) (5) (6)

Availability of Fox News via cable in 2000 0.0046 0.0178 0.0147 0.0072 0.0071 0.01

(0.0039) (0.0051)*** (0.0061)** (0.0026)*** (0.0028)** (0.0035)***

Change in log (voting-age population) bw. 1996 and 2000 0.3655 0.3707 0.3641

(0.0427)*** (0.0440)*** (0.0425)***

Fox News in 2000* (New York race) 0.0039 ⫺0.0017 0.0033

(0.0067) (0.0060) (0.0067)

Republican vote share in 1996 presidential elections 0.8295 0.8432 0.8289

(0.0111)*** (0.0146)*** (0.1111)***

Fox News in 2000* (swing district) ⫺0.0207 ⫺0.0042

(0.0087)* (0.0047)

Fox News in 2000* (Republican district) ⫺0.0177 ⫺0.0075

(0.0090)** (0.0054)

Control variables

Census controls: 1990 and 2000 XXXXXX

Cable system controls XXXXXX

U. S. House district ﬁxed effects X — X X — X

County ﬁxed effects — X — — X —

0.6151 0.6863 0.658 0.9768 0.9829 0.9768

NN⫽ 9,256 N ⫽ 9,256 N ⫽ 9,256 N ⫽ 8,192 N ⫽ 8,192 N ⫽ 8,192

Notes: An observation in the OLS regression is a town in one of the twenty-eight U. S. states in the sample. In columns (1) through (3), the dependent variable is the log of total votes cast in

the 2000 presidential elections minus the same variable for the 1996 elections and the change in the log of the population over 18 between 1996 and 2000 is a control variable. The population data

for 1996 is interpolated from the 1990 and 2000 Census. In columns (4) through (6), the dependent variable is the two-party Republican vote share for the 2000 Senate election, and the vote share

in the presidential elections in 1996 in the same town is a control variable. The variable “Availability of Fox News via cable in 2000” is a binary variable that equals one if Fox News was part of the

town’s local cable package in 2000. The Census controls are twelve demographic variables from the Census, present both in the 2000 values and in differences between 2000 and 1990. The Cable

system controls are deciles in the number of channels provided and in the number of potential subscribers. All controls are listed in Appendix II.

The indicator variables “swing district” and “Republican district” are determined dividing the 9,256 observations into thirds based on the two-party Republican vote share in the

2000 presidential elections at the U. S. House District level. The variable “swing district” indicates a district in the middle third (vote share between .49 and .552). The variable

“Republican district” indicates a district in the top third (vote share higher than .552). The omitted category indicates the Democratic districts. Fox News in 2000* (New York race)

is the interaction of the variable “Availability of Fox News via cable in 2000” and an indicator for New York’s senatorial race between Hillary Clinton and Rick Lazio, the only

senatorial race in 2000 highly covered in the Fox News programming. Robust standard errors clustered by local cable company in parentheses. The observations are weighted by total

votes cast in the 1996 presidential election.

* signiﬁcant at 10 percent; ** signiﬁcant at 5 percent; *** signiﬁcant at 1 percent.

1215THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

elasticity ␥ of the change in votes cast with respect to the change

in population is 0.37. The turnout effect is concentrated in the

more Democratic districts (column (3)). Together with the ﬁnding

that the impact of Fox News on vote share is larger in the more

Democratic areas, this suggests that the main effect of Fox News

was to induce nonvoters in Democratic districts to turn out and

vote Republican.

Overall, Fox News entry into a market appears to have

mobilized new voters, especially in Democratic districts. How-

ever, the evidence is not as consistent as for the effect on vote

share.

III.F. Senate Elections

The previous ﬁndings suggest that Fox News had a signiﬁ-

cant effect on the Republican vote share and on turnout in the

presidential election. In this section, we consider whether the

effect of Fox News extends to local politics not covered by Fox

News. This allows us to test whether the Fox News effect is

candidate-speciﬁc or a general ideological shift.

Senate elections are a good test in this respect because a

large majority of Senate races fail to get national coverage. These

elections are similar to local elections for which, unfortunately, no

town-level data set is available. At the same time, one or two

Senate races per year attract substantial national coverage, al-

most like presidential races. This allows us to compare the effect

of Fox News on races that were not covered, where only ideolog-

ical shifts should matter, to the effect on covered races, where

candidate-speciﬁc coverage also could matter. In 2000, the Senate

race that got the most coverage in Fox News by a wide margin

was the Hillary Clinton–Rick Lazio race in New York State.

These two candidates had ninety-nine mentions in the O’Reilly

Factor and the Hannity & Colmes show in the two months prior

to the 2000 elections, with most mentions critical of Hillary Clin-

ton.

All the other Senate candidates running in the 2000 cam-

paign combined got a total of seventy-three mentions, with Joe

Lieberman, who was typically mentioned because of his vice-

presidential race, getting the lion’s share of these mentions.

We examine whether Fox News impacted the vote share in

14. From the O’Reilly Factor of October 31, 2000: “Mr. Gore does have some

honesty issues about campaign ﬁnance, but they pale beside the deceit factory the

Clintons have set up.”

1216 QUARTERLY JOURNAL OF ECONOMICS

Senate elections and whether it had a differential effect for the

Clinton–Lazio race. We denote by d

the indicator variable for

the New York Senate races. We estimate the speciﬁcation

(4) v

k,2000

R,Sen

⫽ ␣ ⫹ ␣

k,1996

R,Pres

⫹ ␤

k,2000

FOX

⫹ ␾

k,2000

FOX

ⴱ d

⫹ ⌫

2000

k,2000

⫹ ⌫

00–90

k,00–90

⫹ ⌫

k,2000

⫹ ε

where ␤

indicates the effect of Fox News on Senate races other

than New York and ␾

indicates the differential effect for the

featured New York race. This speciﬁcation controls for the 1996

presidential vote share.

Columns (4)–(6) in Table VII report the results. The effect of

Fox News on nonfeatured Senate races is large and signiﬁcant,

0.0072 with district (column (4)) and 0.0071 with county ﬁxed

effects (column (5)). Compared to this effect, the impact on the

New York race is not signiﬁcantly different, although the stan-

dard errors on the coefﬁcient ␾

are relatively large. We then test

for heterogeneity by political areas (column (6)). Consistent with

the ﬁndings for presidential elections, Fox News had the largest

impact in Democratic districts.

Fox News affected voting also in nonfeatured Senate races,

especially in Democratic districts. We fail to ﬁnd a stronger effect

for highly emphasized races. These results suggest that Fox News

exposure induced a generalized ideological shift, as opposed to a

candidate-speciﬁc effect.

IV. INTERPRETATIONS

The introduction of a (comparatively speaking) conservative

news channel increased the vote share of Republican candidates.

We now evaluate the magnitude of this effect by estimating the

share of the audience that was convinced by Fox News to vote

Republican. We compare this persuasion rate to other media

effects in the literature and put forward interpretations.

IV.A. Persuasion Rates

Model. To compute persuasion rates, we compare treatment

towns T, where Fox News is available via cable, and control

towns C, where Fox News is not available via cable. We denote by

15. The results are similar if we control for the 1994 Senatorial vote share

instead [see DellaVigna and Kaplan 2006]. The disadvantage of this speciﬁcation

is that it restricts the sample to 2,037 towns in ﬁve states.

1217THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

r the share of Republican voters and by d the share of Democratic

voters, before the introduction of Fox News. For simplicity, we

neglect third parties. Consequently, (1 ⫺ r ⫺ d) denotes the

share of nonvoters. Since the two types of towns have similar

political outcomes in the pre-Fox News period conditional on a set

of controls (Tables II and III), we assume that r and d are the

same in towns T and C.

A fraction e of the town population is exposed to Fox News,

after the nationwide introduction. Exposure e is higher in treat-

ment towns; that is, e

⬎ e

ⱖ 0. We allow nonzero exposure e

in control towns because, for example, of the availability of sat-

ellite which broadcasts Fox News to subscribers in both towns.

For simplicity, we also assume that the exposure e

to Fox News

in town j is independent of political afﬁliation. That is, we assume

that Republicans are as likely as Democrats or nonvoters to

watch Fox News when available. While Republicans are more

likely to watch Fox News (Table I), we cannot rule out that this

captures the causal convincing effect of Fox News, rather than

differential exposure e

by party.

The key parameter is f, the fraction of the audience that is

convinced by Fox News to vote Republican. This persuasion rate,

f, applies equally to Democratic voters and to nonvoters, that is,

to a fraction (1 ⫺ r) of the Fox News audience e

, where j ⫽ T, C.

Therefore, the introduction of Fox News increases the fraction

voting Republican by (1 ⫺ r)e

f. The two-party vote share v

town j, with j ⫽ T, C, equals

(5) v

⫽

r ⫹ 共1 ⫺ r兲e

r ⫹ d ⫹ 共1 ⫺ r ⫺ d兲e

(Turnout increases since Fox News induces a fraction f of the

nonvoters to vote Republican.) Using expression (5), we solve for

the difference in vote share between treatment and control towns,

⫺ v

, the equivalent of ␤

in the data. We obtain v

⫺ v

⫽

⫺ e

) fd/t

, where t

⬅ (r ⫹ d ⫹ (1 ⫺ r ⫺ d)e

f) is the

turnout in town j. The implied persuasion rate f is

(6) f ⫽

⫺ v

共e

⫺ e

兲共1 ⫺ r兲

共1 ⫺ r兲t

The ﬁrst term in expression (6) is the inﬂuence rate per

treated population, and the second term is a factor correcting for

turnout effects. The numerator of the ﬁrst term, v

⫺ v

, is the

1218 QUARTERLY JOURNAL OF ECONOMICS

shift in Republican vote share due to the availability of Fox News

via cable. The denominator, (e

⫺ e

)(1 ⫺ r), normalizes this

vote shift by the share of population at risk of treatment, that is,

by the differential exposure to Fox News, times the share of

non-Republicans.

The second term, which disappears if turnout is perfect (r ⫹

d ⫽ 1), captures the differential convincing effect of Fox News on

a Democrat and a nonvoter. In both cases, Republicans gain a

vote but only in the ﬁrst case does the Democratic party lose a

vote. The larger the ratio of non-Republicans (1 ⫺ r) to Demo-

crats d, hence, the bigger is the convincing impact for a given vote

share change. In addition, the term t

corrects for the fact that

a higher turnout t

increases the denominator of expression (5),

and, therefore, decreases the impact of f on v

Audience Data. We estimate the differential exposure (e

⫺

) in expression (6) using the microlevel Scarborough data on

television audiences described in Section II. We use the sub-

sample of 11,388 respondents for whom we observe the zip code of

residence and for whom we can match by zip code to the cable

data on availability of Fox News (Table I, columns (4)–(6)). We

use the “diary audience” measure since the “recall audience”

measure is not available for most of this sample. We aggregate

the data at the town level to maximize comparability to the

speciﬁcations in the rest of the paper. For each town k of the 568

towns in this sample, e

FOX

is the fraction of town residents in the

Fox News audience. We estimate

(7) e

FOX

⫽ ␣ ⫹ ␤

k,2000

FOX

⫹ ⌫

2000

k,2000

⫹ ⌫

00–90

k,00–90

⫹ ⌫

k,2000

⫹ ε

The regression is weighted by the number of respondents in a

town, and the standard errors are clustered at the level of the

local cable company. The coefﬁcient ␤

is the differential Fox

News diary audience due to Fox News availability via cable in the

town.

Table VIII shows the results. In the speciﬁcation without

controls (column (1)), the availability of Fox News induces 2.7

percent (␤

⫽ 0.0270) additional town residents to watch Fox

News for at least a full half hour per week. The estimate is

signiﬁcant and sizeable. In towns where Fox News is not avail-

able via cable, 2.62 percent (␣ˆ ⫽ 0.262) of the residents still watch

1219

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

TABLE VIII

THE EFFECT OF FOX NEWS EXPOSURE ON FOX NEWS AUDIENCE:PERSUASION RATES (SCARBOROUGH DATA)

Dep. var.

Share of town respondents that watched at least thirty minutes of a channel in past week

Watched Fox News Watched CNN

(1) (2) (3) (4) (5) (6) (7)

Availability of Fox News via cable

in 2000

0.027 0.0371 0.0251 0.0346 0.0251 0.0042 0.0045

(0.0058)*** (0.0105)*** (0.0082)*** (0.0116)*** (0.0121)** (0.0114) (0.0104)

Availability of Fox News via cable

in 2003

0.0016

(0.0090)

Constant 0.0262 0.0928 ⫺0.0531 0.1317 0.0947 0.7213 0.0917

(0.0036)*** (0.1046) (0.1316) (0.1102) (0.0054)*** (0.1674)*** (0.2119)

Control variables

Census controls: 1990 and 2000 — X X X — X X

Cable system controls — X X X — X X

U. S. House district ﬁxed effects — X — X — X —

County ﬁxed effects — — X — — — X

2SLS estimates of persuasion rates

Estimates using (predicted)

recall audience measure

0.0339 0.0827

(0.0151)** (0.0298)***

Estimates using diary audience

measure

0.1162 0.2829

(0.0518)** (0.1020)***

0.0655 0.3105 0.3507 0.3148 0.0217 0.3872 0.4262

NN⫽ 568 N ⫽ 568 N ⫽ 568 N ⫽ 545 N ⫽ 568 N ⫽ 568 N ⫽ 568

Notes: An observation in the OLS regression is a town for which both Scarborough data on diary audience as well as cable and election data are available. The variable

“Availability of Fox News via cable in 2000” is a binary variable that equals one if Fox News was part of the town’s local cable package in 2000 and similarly for the variable

“Availability in Fox News via cable in 2003.” The persuasion rate is the share of population exposed to Fox News that is persuaded to vote Republican and is computed at the ratio

of the impact of Fox News on voting (Table IV) to the impact of Fox News on audience (this table), corrected for political composition of the audience. The Census controls are twelve

demographic variables from the Census, present both in the 2000 values and in differences between 2000 and 1990. The controls for cable features are deciles in the number of

channels provided and in the number of potential subscribers. All controls are listed in Table X. The standard errors for the persuasion rates are computed using the Delta Method.

The Fox News audience according to the recall audience measure is an indicator variable for respondents who stated that they watched a channel in the past seven days. The

Fox News audience according to the diary audience measure is an indicator variable for whether the respondent watched at least a full thirty-minute block of Fox News in the survey

week. Additional details on persuasion rates are in the text. Robust standard errors clustered by local cable company in parentheses. The observations are weighted by the total

number of survey respondents in the town.

* signiﬁcant at 10 percent; ** signiﬁcant at 5 percent; *** signiﬁcant at 1 percent.

1220 QUARTERLY JOURNAL OF ECONOMICS

Fox News for at least a full half hour per week. About half of the

Fox News audience, therefore, watches Fox News in ways other

than via cable, possibly via satellite. This ﬁnding could also be

due to measurement error in our measure of availability via

cable. In either case, the estimates in Section III are likely to

understate the impact of Fox News on voting, since they capture

only the impact of Fox News availability via cable.

In columns (2) and (3), we add the Census, cable, and geo-

graphic controls used in the body of the paper. The estimated

differential exposure rates are ␤

⫽ 0.0371 with congressional

district ﬁxed effects and ␤

⫽ 0.0251 with county ﬁxed effects.

Interestingly, introducing control variables and district ﬁxed ef-

fects increases the estimated ␤

As a ﬁrst placebo test, we show that availability of Fox News

via cable in 2003 does not increase audience rates in 2000 (col-

umn (4)). As a second placebo test, we show that, once we add

controls (columns (6) and (7)) availability of Fox News in 2000

does not increase the audience for CNN (CNN is available in all

towns in our sample).

Persuasion Rates. We estimate the persuasion rate f using

expression (6). We obtain the differential exposure rate e

⫺ e

as the coefﬁcient ␤

of columns (2) and (3) in Table VIII. We ﬁrst

use the more inclusive recall audience measure. Since we cannot

directly estimate the model (7) for the recall audience variable,

we multiply the estimates of ␤

by a conversion rate, the ratio

between the aggregate recall audience and diary audience for

CNN, that is, 35.3/10.3 ⫽ 3.43 (Table I, column (4)). (The ratio

would be somewhat higher if we used the audience measures for

Fox News.) The implied estimates for the differential exposure

rate eˆ

⫺ eˆ

are 0.1271 with district ﬁxed effects and 0.0860 with

county ﬁxed effects.

We evaluate the political variables t

, t

, r, and d using the

sample averages of the 2000 elections. We weight the averages by

total votes cast in 2000 to better approximate the individual-level

expressions (5) and (6). The average weighted turnout in 2000 as

a share of the voting-age population is 0.560, and it is very similar

in Fox News and non-Fox News towns, hence t

⫽ t

⫽ 0.560.

The percentage of Democratic voters d is the product of the

16. The average self-reported turnout in the Scarborough survey is 69.3

percent, but self-reported turnout is known to overstate the actual ﬁgure.

1221THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

turnout rate t and the average weighted Democratic two-party

vote share in 2000 in our sample, that is, 0.560 ⴱ (1 ⫺ 0.453) ⫽

0.306. This implies that f ⫽ 1.024 ⴱ (v

⫺ v

)/(e

⫺ e

Combining the estimates of these variables (e

⫺ e

, t

d) with the estimates of the voting impact (v

⫺ v

) from Table

IV, we compute persuasion rates f using the (predicted) recall

audience measure. The standard errors for f take into account the

uncertainty in both the audience regressions (Table IV) and the

vote share regressions (Table VIII).

With congressional district

ﬁxed effects we get f ⫽ 1.024 ⴱ (0.0042/0.1271) ⫽ 0.0339; that

is, Fox News convinced 3.39 percent of its viewers that were not

already voting Republican to do so. With county ﬁxed effects, we

derive f

⫽ 1.024 ⴱ (0.0069/0.0860) ⫽ 0.0827; that is, Fox News

convinced 8.27 percent of its audience. Both estimates are signif-

icantly different from zero, but are fairly imprecisely estimated

due to the small sample of the audience regressions.

In Table VIII we also report the persuasion rates f

computed

with respect to the diary audience measure. The persuasion rates

are 3.42 times larger if e

⫺ e

is measured using the diary data

as the measure of audience. The resulting estimates f

⫽ 0.1162

(district ﬁxed effects) and f

⫽ 0.2829 (county ﬁxed effects) imply

large persuasion effects of the media. We summarize these re-

sults in Table VIII and in the ﬁrst two rows of Table IX.

Robustness. The estimates of the persuasion rate are robust

to different estimates of the political parameters. If, instead of

using weighted means, we use the unweighted means (t ⫽ 0.583

and d ⫽ 0.583 ⴱ (1 ⫺ 0.538)), we obtain f

⫽ 0.0417 with district

ﬁxed effects and f

⫽ 0.1012 with county ﬁxed effects. These

effects are in the ballpark of the benchmark estimates.

The persuasion rate estimates are more sensitive to assump-

tions about the exposure rate. A factor that leads to higher per-

suasion rates is the self-selection of Republicans in the Fox News

audience. In Table VIII, we estimate the selective exposure e

⫺

in (7) using the whole population rather than just Democratic

voters and nonvoters. To the extent that Republicans self-select

17. The standard errors are computed using the Delta method, taking into

account also the covariance between the estimated ␤

in the vote share in the

audience regressions (in the sample of towns for which both are available). The

standard errors do not take into account the (limited) uncertainty in the estimate

of t

, t

, d, and of the conversion rate.

1222 QUARTERLY JOURNAL OF ECONOMICS

in the Fox News audience, this downward biases the estimate

of f.

Conclusion. The estimates using the recall audience imply

that Fox News convinced 3 to 8 percent of its audience to shift its

voting behavior toward the Republican party, a sizeable media

persuasion effect. Alternative estimates using the more restric-

tive diary audience measure lead to estimates of the persuasion

rate between 0.11 and 0.28, corresponding to large media effects.

IV.B. Persuasion Rates in the Literature

We estimate persuasion rates f for other studies in the liter-

ature summarized in Table IX. We discuss ﬁeld experiments,

laboratory experiments, and surveys.

Field Experiments. In a series of ﬁeld experiments [Green

and Gerber 2004], households within a precinct are randomly

selected to receive turn-out-the-vote treatments (canvassing,

phone calls, or leaﬂets) right before an election. Turnout is mea-

sured using ofﬁcial individual voting records. In other experi-

ments, the randomization is done at the precinct level, and pre-

cinct-level turnout is compared across precincts. Using the same

notation as in Section IV.A and denoting by t the turn-out rate,

we assume that the treatment convinces a fraction f of the people

that do not usually turn out and are exposed, that is, (1 ⫺ t)e

, for

j ⫽ T, C. It follows that t

⫽ t ⫹ f(1 ⫺ t)e

and t

⫺ t

⫽ (1 ⫺

t)(e

⫺ e

) f. This implies

(8) f ⫽

⫺ t

⫺ e

共1 ⫺ t兲

In these experiments, e

⫽ 0 since no one in the control group is

treated, hence t ⫽ t

. In Table IX, we summarize the treatment,

election type, year, location, and sample size of ﬁve such experi-

ments. Using the turnout rates in the control (t

) and treatment

) groups and the exposure rate e

⫺ e

, we compute the

persuasion rate f using expression (8). Canvassing and phone

calls convinced between 4 and 26 percent of nonvoters to turn out

to the polls.

More recently, Gerber, Karlan, and Bergan [2006] randomly

18. Unfortunately, we cannot restrict the estimation of (7) to non-Republi-

cans, since the party identiﬁcation variable is measured in 2000 and it captures

the causal effect of Fox News, as well as sorting.

1223THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

TABLE IX

COMPARISON WITH PERSUASION RATES IN OTHER MEDIA STUDIES

Paper

Variable: persuasion rate f (share of listeners convinced by media)

Treatment

Election

type or

question Variable t Year Place Sample size

Control

group

Treatment

group t

Exposure

rate

⫺ e

Persuasion

rate

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)

Fox News Study

DellaVigna and

Kaplan [2006]

Fox News

exposure,

district f.e. Presidential

election

Republican

vote share

2000 28 U. S.

states

N ⫽

66,372,804

0.556 0.560 0.127 0.034/0.116

Fox News

exposure,

county f.e.

0.556 0.563 0.086 0.083/0.283

Field Experiments

Gerber and Green

[2000]

Door-to-door

canvassing

Federal

elect.

Turnout 1998 New Haven N ⫽ 14,473 0.422 0.463 0.270 0.263

Canvassing ⫹

mail ⫹ calls

Federal

elect.

Turnout 1998 New Haven N ⫽ 14,850 0.422 0.448 0.270 0.167

Green, Gerber, and

Nickerson [2003]

Door-to-door

canvassing

Local elect. Turnout 2001 6 cities N ⫽ 18,933 0.286 0.310 0.293 0.118

Green and Gerber

[2001]

Phone calls by

youth vote

General

elect.

Turnout 2000 4 cities N ⫽ 4,377 0.660 0.711 0.737 0.205

Phone calls 18–

30-year-olds

General

elect.

Turnout 2000 2 cities N ⫽ 4,377 0.405 0.416 0.414 0.045

Gerber, Karlan,

and Bergan

[2006]

Free

subscription

to Washington

Post

Governor

elect.

Dem. share

of votes

2005 Washington N ⫽ 1,011 0.291 0.363 0.940 0.109

1224 QUARTERLY JOURNAL OF ECONOMICS

TABLE IX

(CONTINUED)

Paper

Variable: persuasion rate f (share of listeners convinced by media)

Treatment

Election

type or

question Variable t Year Place Sample size

Control

group

Treatment

group t

Exposure

rate

⫺ e

Persuasion

rate

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)

Laboratory

Experiments

Ansolabehere and

Iyengar [1995]

Laboratory

exposure to

30-second

political ad

Governor

elect.

Vote share

for party

sponsoring

1990

Southern

California

N⫽1,716 0.530 0.568 1.000 0.082

Senate

elect.

1992

Mayor elect. 1993

Surveys

Kull, Ramsay, and

Lewis [2003]

Respondent

watches Fox

News

Did U. S.

ﬁnd

WMD in

Iraq?

Share of yes

answers

2003 USA N⫽8,634 0.220 0.330 1.000 0.141

Gentzkow and

Shapiro [2004]

Respondent

watches CNN

Did Arabs

do 9/11

attack?

Share of yes

answers

2002 Arab

countries

N⫽2,457 0.215 0.280 1.000 0.083

Respondent

watches Al

Jazeera

2002 N⫽2,457 0.215 0.133 1.000 0.105

Notes: Calculations of media effect by the authors based on data from the papers cited. Columns (7) and (8) report the share of Republican voters in the control and treatment

group. Column (9) reports the exposure rate, that is, the difference between the treatment and the control group in the share of people exposed to the treatment. Column (10) computes

the estimated persuasion rate f as (tT ⫺ tC)/((eT ⫺ eC)*(1 ⫺ tC)), except in the ﬁrst row (see text). The persuasion rate denotes the share of the audience that was not previously

convinced and that is convinced by the message. The data for this paper refer to the estimates obtained using the (predicted) recall audience measure and the diary audience measure,

respectively. The data for the Gerber, Karlan, and Bergan [2006] study is courtesy of the authors. For the Ansolabehere and Iyengar [1995] study, we use the data in Tables B1.1

and B2.4, neglecting voters that state the intention not to vote. We obtain the baseline share of vectors t

⫺{C}

from Table B1.1 as the weighted average share of the subjects with the

same party afﬁliation as the sponsoring party: (50/(50 ⫹ 38)) ⴱ 48/(46 ⫹ 18) ⫹ (38/(50 ⫹ 38)) ⴱ 18/(46 ⫹ 18).

1225THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

assign subscriptions to a right-wing newspaper (Washington

Times) or a left-wing newspaper (Washington Post), and consider

the effect on stated voting behavior in a post-election survey.

They ﬁnd a substantial increase in the share of (stated) Demo-

cratic voters for exposure to the left-wing newspaper, correspond-

ing to a persuasion rate f of 0.109. (We use expression (8) where

t is the share of Democratic votes out of all survey respondents,

including nonvoters, and where we assume that all recipients of

a subscription read the newspaper.) However, they also ﬁnd that

the share of Democratic voters increases after exposure to the

right-wing paper, albeit insigniﬁcantly.

Laboratory Experiments. Ansolabehere and Iyengar (1995]

expose experimental subjects to thirty-second political advertise-

ments supporting a candidate (or criticizing the opposite candi-

date). They then elicit beliefs and voting intentions at the end of

the experiment. In Table IX we summarize the ﬁndings for three

sets of experiments with 1,716 total subjects. On average, expo-

sure to one advertisement yields a sizeable persuasion rate f of

0.08 on the stated vote share for the sponsoring party. Other

experiments by the authors (results not reported) lead to persua-

sion rates of similar or larger magnitudes.

Surveys. Following Lazarsfeld, Berelson, and Gaudet [1944],

political scientists have widely used surveys to assess the impact

of the media. A survey in this tradition [Kull, Ramsay, and Lewis

2003] ﬁnds that 33 percent of Fox News watchers believe (erro-

neously) that weapons of mass destruction were found in Iraq by

October 2003, compared to 22 percent for the overall sample. This

implies a persuasion rate f of 0.141 (Table IX). Gentzkow and

Shapiro [2004] examine the effect of media exposure in the Is-

lamic world. The CNN audience was 30 percent more likely to

believe, and the Al Jazeera audience was 40 percent less likely to

believe that Arabs carried out the 9/11 attacks, compared to

respondents who watched neither. The estimates imply persua-

sion rates between 0.08 and 0.10. While the survey estimates

could be due to sorting rather than causal effects, the implied

persuasion rates are quite close to the experimental estimates.

IV.C. Explanations

Our estimates imply that Fox News convinced a signiﬁcant

portion of its audience to vote Republican. We consider three

explanations for this ﬁnding: one statistical, one rational, and one

1226 QUARTERLY JOURNAL OF ECONOMICS

nonrational. In DellaVigna and Kaplan [2006], we present a

model of the last two explanations.

1. Endogeneity Bias. The ﬁndings may be spurious and

induced by entry of Fox News in towns that were indepen-

dently becoming more conservative. Contrary to this in-

terpretation, conditional on the controls, vote shares in

1996 and voting trends in 1988 –1992 do not predict the

introduction of Fox News (Table III). Moreover, the intro-

duction of Fox News does not predict political voting

trends between 1992 and 1996 (before the introduction)

(Table VII). Fox News only affects vote share changes

between 1996 and 2000. Endogeneity of Fox News intro-

duction is unlikely to explain the results.

2. Rational Learning. To the extent that voters are initially

uncertain about the bias of Fox News, exposure will have

a (temporary) effect on beliefs and voting. Voters attribute

the positive coverage of George W. Bush in 2000 partly to

Republican bias of the media source (Fox News) but partly

also to high quality of the Republican candidate (Bush). A

ﬁrst issue with this interpretation is that, arguably, by the

year 2000 the conservative slant of Fox News should have

been clear. Second, this explanation makes the prediction

that the media effect should disappear over time as voters

become aware of Fox News’ political slant. Contrary to

this prediction, the Fox News effect over the 2000 –2004

period gets, if anything, larger (Table V).

3. Nonrational Persuasion. A behavioral interpretation is

that viewers do not discount media bias strongly enough

[Cain, Loewenstein, and Moore 2005] and therefore are sub-

ject to nonrational persuasion upon exposure. This interpre-

tation can explain the persistence of the Fox News effect.

The two most plausible explanations, learning and persua-

sion, have very different long-run implications. Rational learning

predicts that Fox News’ impact is temporary. Nonrational per-

suasion predicts that Fox News permanently altered voting pat-

terns in the United States.

Whether the effect is rational or not, it would be interesting

to know the exact mechanism by which Fox News affected voting.

The Senate results suggest that the effect is not due only to

19. The increase in the effect over time may also be explained by increasing

audience rates.

1227THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

candidate-speciﬁc coverage, but rather to a general ideological

shift. Beyond this, we cannot tell if the effect is due to conserva-

tive slant of the news or to the choice of topics like National

Security that favor Republicans, as implied by the agenda setting

theory [Cohen 1963].

V. CONCLUSION

This paper studies the impact of media bias upon voting. We

consider one of the most dramatic changes in the U. S. media in

recent years, the sudden introduction and expansion of the Fox

News cable channel from 1996 to 2000. We exploit the natural

experiment induced by the timing of the entry of the Fox News

channel in local cable markets.

We ﬁnd a signiﬁcant effect of exposure to Fox News on voting.

Towns with Fox News have a 0.4 to 0.7 percentage point higher

Republican vote share in the 2000 presidential elections, com-

pared to the 1996 elections. A vote shift of this magnitude is likely

to have been decisive in the 2000 elections. We also ﬁnd an effect

on vote share in Senate elections, which Fox News did not cover,

suggesting that the Fox News impact extends to general political

beliefs. Finally, we ﬁnd evidence that Fox News increased turn-

out to the polls.

Based on this evidence and on microlevel audience data, we

estimate that exposure to Fox News induced a substantial per-

centage of the non-Republican viewers to vote for the Republican

party, 3 to 8 percent according to the more inclusive audience

measure, and 11 to 28 percent according to the more restrictive

measure. These estimates are consistent with ﬁeld, laboratory,

and survey evidence of media effects on political beliefs and

voting. We interpret the persuasion effect as a temporary learn-

ing effect for rational voters or a permanent effect for voters

subject to nonrational persuasion. These results suggest that the

media can have a sizeable political impact.

This paper leaves a number of open questions. First, while we

analyze the extensive margin of voting, we do not consider the

effect on the intensity of political convictions of Republican vot-

ers. In ongoing research, we study the impact on the intensive

margin of campaign contributions. Second, we have not directly

examined the impact on policy-making. While a vote shift toward

Republicans is likely to induce a change in policy [Lee, Moretti,

and Butler 2004], direct evidence documenting this effect would

1228 QUARTERLY JOURNAL OF ECONOMICS

be interesting. Finally, we hope that more evidence on the effect

of other sources of media bias, such as local papers and radio talk

shows, will complement the evidence in this paper.

UC BERKELEY AND NBER

IIES, STOCKHOLM UNIVERSITY

APPENDIX I: DATA

A. Cable Data

The source for the cable data is the Television and Cable

Factbook 2001 (referring to year 2000). A typical entry from the

Pennsylvania State section is

“KING OF PRUSSIA (Pa)—Comcast Cable. Counties: Dela-

ware and Montgomery. Also serves: Collegeville, Grater-

ford, Graterford Prison, Gulph Mills, [. . .] Upper Provi-

dence Twp. (Delaware County), Wayne. Account No:

PA0050. [. . .]

Basic Service Subscribers 17,692. [. . .] Programming (re-

ceived off-air): WFMZ-TV (I); WLVT-TV (P) Allentown;

WGTW (I) Burlington; KYW-TV (C) [. . .]. Programming

(via satellite): C-SPAN, EWTN; Fox Family Channel;

MSNBC [. . .] Fee: [. . .] $21.95 monthly. [. . .]

Expanded Basic Service Subscribers 17,138. Program-

ming (via satellite): A&E; AMC; Bravo; CNBC; CNN; Com-

edy Central; [. . .]. Fee: N.A.

Pay Service 1 Pay units: 845. Programming (via satellite):

Cinemax. Fee: [. . .] $8.95 monthly. [. . .]

Ownership: Comcast Cable Communications Inc.”

Each entry is listed by state under the principal community,

which is the town where the local cable company’s business ofﬁce

is located. The additional communities reached by the local cable

company are listed in alphabetical order, typically without indi-

cation of the county, which is listed separately (the number of

counties is rarely more than three). In the example above, the

communities listed belong to one of two counties (Delaware and

Montgomery) in Pennsylvania. Since we do not know which be-

longs to which, we generate all combinations of town and county,

except in cases where the county is explicitly listed as in “Upper

Providence Twp. (Delaware County).” When we match the cable

data with the Census and election data, the ﬁctitious town–

county combinations drop out. The only possibility of match error

is if there are two towns with the same name in the multiple

1229THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

counties listed, but in this case we expect the county to be explic-

itly listed next to the town name. In a few cases, the communities

reached are indicated only as fractions of a county, such as

“Alameda County (Western borders).” We exclude these commu-

nities, since we cannot match them to voting data. As long as

these communities do not include other separately listed towns in

the cable data, their deletion will not bias the measure of cable

offerings for the other towns. As a robustness check, we recom-

pute the results in the paper excluding the 149 counties which

include one such community where Fox News is available. All the

results hold in this smaller sample of 8,262 towns.

The Basic Service description lists all the local television

stations that the cable company rebroadcasts under the heading

“Programming (received off-air).” We disregard these stations.

We estimate instead the number of cable channels broadcast in

the “Programming (via satellite)” section. To save coding time,

the total number of channels is estimated counting the number of

lines listing cable channels in the Basic and Expanded Basic 1, 2,

and 3 Services. The estimated number of channels follows by

multiplying this number by 2.5, a conversion rate estimated on a

subsample of forty cable companies. Over this subsample, a re-

gression of actual number of channels on forecasted number of

channels yields an R

of 0.95 and a coefﬁcient of 1.

Finally, it is worth noting that sometimes the number of

subscribers or (as in this case) the price of the subscription is

missing or refers to previous years.

B. Election Data

In the aggregation of voting information to the town level, we

drop precincts such as “Precinct 1” where the transformation

algorithm leads to an empty name. In States like Alabama, Ar-

kansas, and Tennessee, the aggregation procedure generates a

very large number of localities because precinct names are often

incorrectly identiﬁed as a locality by our code. (These ﬁctitious

towns drop out from the ﬁnal sample, since they do not match to

Census and cable data.) The New England States, instead, have

a small number of exactly identiﬁed towns because the election

data is reported at the town level.

For the towns that are in multiple districts, we code the town

as belonging to the district where the largest fraction of the

town’s population is represented.

1230

QUARTERLY JOURNAL OF ECONOMICS

APPENDIX II: List of Controls for Tables III and IV

Regression of Fox News

on determinants

(Table III)

Regression of vote share

on Fox News

(Table IV)

Coefﬁcient Std. error Coefﬁcient Std. error

(1) (2) (3) (4)

Census controls 2000

Population ⫺0.0004 (0.0013) ⫺0.0003 (0.0001)***

High school 0.0334 (0.2233) 0.0252 (0.0160)

Some college ⫺0.0218 (0.1964) ⫺0.0664 (0.0141)***

College graduate 0.0672 (0.1599) ⫺0.097 (0.0103)***

Male 0.2285 (0.2859) 0.1146 (0.0208)***

African American ⫺0.013 (0.1086) ⫺0.0547 (0.0061)***

Hispanic ⫺0.1155 (0.1973) ⫺0.0571 (0.0130)***

Employment 0.0759 (0.1225) 0.0367 (0.0089)***

Unemployment 0.3511 (0.3768) 0.1212 (0.0265)***

Married ⫺0.1057 (0.1419) 0.0033 (0.0078)

Income ⫺0.0124 (0.0072)* ⫺0.0012 (0.0004)***

Urban ⫺0.0293 (0.0251) ⫺0.0073 (0.0014)***

Census controls 2000–1990

Population ⫺0.0189 (0.0106)* 0.0018 (0.0005)***

High school 0.0132 (0.1997) 0.0136 (0.0136)

Some college ⫺0.1716 (0.1931) 0.0596 (0.0154)***

College graduate 0.0351 (0.2097) 0.0841 (0.0127)***

Male ⫺0.218 (0.3099) ⫺0.0311 (0.0238)

African American ⫺0.3921 (0.2173)* 0.0687 (0.0181)***

Hispanic ⫺0.0138 (0.3556) ⫺0.054 (0.0206)***

Employment ⫺0.0367 (0.1453) ⫺0.0209 (0.0109)*

Unemployment ⫺0.3466 (0.2663) ⫺0.0594 (0.0229)***

Married ⫺0.0786 (0.1238) ⫺0.0105 (0.0111)

Income 0.0157 (0.0118) 0.0011 (0.0010)

Urban ⫺0.0039 (0.0280) 0.0029 (0.0018)

Decile in potential subscribers

Decile 2 ⫺0.006 (0.0188) ⫺0.0007 (0.0032)

Decile 3 0.0534 (0.0249)** ⫺0.0006 (0.0031)

Decile 4 0.0499 (0.0295)* ⫺0.0022 (0.0031)

Decile 5 0.0388 (0.0334) ⫺0.0053 (0.0033)

Decile 6 0.0563 (0.0369) ⫺0.006 (0.0033)*

Decile 7 0.0259 (0.0410) ⫺0.011 (0.0034)***

Decile 8 0.022 (0.0387) ⫺0.0105 (0.0035)***

Decile 9 ⫺0.0056 (0.0432) ⫺0.0124 (0.0035)***

Decile 10 0.1786 (0.0481)*** ⫺0.0127 (0.0035)***

Decile in number of channels

Decile 2 0.0355 (0.0221) 0.0024 (0.0019)

Decile 3 0.0778 (0.0267)*** 0.002 (0.0021)

Decile 4 0.051 (0.0287)* ⫺0.0005 (0.0023)

Decile 5 0.0394 (0.0344) ⫺0.0011 (0.0021)

Decile 6 0.1122 (0.0278)*** 0.0001 (0.0019)

Decile 7 0.3347 (0.0464)*** 0.0015 (0.0022)

Decile 8 0.4292 (0.0526)*** ⫺0.0017 (0.0023)

Decile 9 0.4113 (0.0541)*** ⫺0.0025 (0.0023)

Decile 10 0.6475 (0.0500)*** ⫺0.0014 (0.0025)

U. S. House district ﬁxed effects XXXX

Notes: An observation in the OLS regression is a town. List of controls for the speciﬁcations with district

ﬁxed effects from Table III (column (4)) and Table IV (column (4)). The number of potential subscribers is the

total population covered by a cable system.

*signiﬁcant at 10 percent; ** signiﬁcant at 5 percent; ***signiﬁcant at 1 percent.

1231THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

APPENDIX III: The Fox News Effect: Comparison with Earlier Results

Dep. var.

Presidential republication vote share change between 2000 and 1996

(1) (2) (3) (4) (5) (6)

Availability of Fox News via cable in

2000

0.0014 0.004 0.0002 0.0022 ⫺0.0003 0.0017

(0.0016) (0.0015)*** (0.0015) (0.0014) (0.0016) (0.0014)

Control variables

Census controls: 1990 and 2000 X X XXXX

Cable system controls X X XXXX

U. S. House district ﬁxed effects X — X — X —

County ﬁxed effects — X — X — X

Speciﬁcations

Unweighted X X XXXX

Include high-measurement-error obs. XXXX

Exclude HI, ND, NJ, WY XX

0.5666 0.6796 0.5574 0.6765 0.5371 0.6641

NN⫽ 9,256 N ⫽ 9,256 N ⫽ 9,802 N ⫽ 9,802 N ⫽ 9,131 N ⫽ 9,131

Notes: An observation in the OLS regression is a town in one of the twenty-eight U. S. states in the sample. The dependent variable is the two-party Republican vote share for

the 2000 presidential election minus the same variable for the 1996 elections. The variable “Availability of Fox News via cable in 2000” is a binary variable that equals one if Fox

News was part of the town’s local cable package in 2000. The Census controls are twelve demographic variables from the Census, present both in the 2000 values and in differences

between 2000 and 1990. The cable system controls are deciles in the number of channels provided and in the number of potential subscribers. All controls are listed in Appendix II.

The speciﬁcations in columns (3) through (6) include 289 towns with multiple cable systems, at least one of which carries Fox News and at least one of which does not, as well as

257 towns with likely voting data problems. The speciﬁcations in columns (5) and (6) exclude observations from the states of Hawaii, North Dakota, New Jersey, and Wyoming. The

speciﬁcations in columns (5) and (6) correspond to the ones in an earlier draft of this paper discussed in Krueger [2005]. Robust standard errors clustered by cable afﬁliate in

parentheses.

* signiﬁcant at 10 percent; ** signiﬁcant at 5 percent; *** signiﬁcant at 1 percent.

1232 QUARTERLY JOURNAL OF ECONOMICS

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