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, theconservative 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 theintroduction 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 thatbroadcast 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 apermanent 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]. Alternatively, behavioral theories [De Marzo, Vayanos, and Zwiebel
2003] and cognitive linguistics theories [Lakoff 1987] suggestthat voters are subject to media persuasion. Understanding theimpact 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 Hamilton, 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), CarnegieMellon University, EUI (Florence), Fuqua, Harvard University (Economics Department 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, andthe NBER 2005 Political Economy and Labor Studies Meetings provided usefulcomments. We also thank the editor (Edward Glaeser) and three referees fordetailed 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, Martin 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 Ebenstein, Devin Pope, Anitha Sivasankaran, and Justin Sydnor provided excellent
research assistance.
© 2007 by the President and Fellows of Harvard College and the Massachusetts Institute ofTechnology.
The Quarterly Journal of Economics, August 2007

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more generally, for models of belief updating. From a policy
perspective, if media bias alters voting behavior, deregulation ofmedia 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” fromhere 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 (Scarborough Research data).
The decentralized nature of the cable industry induced substantial 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 introductionof 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 andthe rest of the media the liberal wing, or Fox News represents theright and the rest of the media the middle.
To analyze whether the change in political information affects 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 voteshare between 1996 and 2000 for the towns that had adopted Fox
News by 2000 with those that had not. Conditional on a set ofgeographic and cable controls, the availability of Fox News is
uncorrelated with town-level demographic controls and withtown-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 Republican 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 and2000, it is still likely to have been decisive in the close presidential elections.
We check our identification strategy with placebo specifica-

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1189

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 withtown characteristics. The effect was smaller in towns with more
cable channels, which is consistent with a moderating effect ofcompetition [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 shareof 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 mostSenate races. This allows us to estimate whether the influence of
Fox News is candidate-specific or whether it extends to generalpolitical 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 theone Senatorial race that Fox News covered heavily, the New YorkState 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 presidential 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 votersand particularly conservative voters in Democratic-leaning
districts.
Overall, we find a sizeable impact of Fox News on the voteshare for Republicans. To quantify the persuasion rate of themedia, we incorporate information on the extent of viewershipand the share of Republicans in the Fox News audience. Using
two different audience measures from Scarborough Researchdata, we compute the impact on the Fox News viewership ofavailability 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 asizeable, and possibly large, persuasion effect.
We compare the persuasion rates estimated in our study with

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the persuasion rates implied by other studies of media effects onpolitical beliefs or voting.1 These studies include field experiments on voter turnout [Green and Gerber 2004] and on party
choice [Gerber, Karlan, and Bergan 2006], laboratory experiments involving exposure to political advertisements [Ansolabehere and Iyengar 1995], and poll studies [Kull, Ramsey, andLewis 2003; Gentzkow and Shapiro 2004]. Our estimates of persuasion rates are in the range of most estimates in the literature.
We consider three explanations of our results. The first explanation is that the findings are spurious and are induced byentry 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 conservative before the entry of Fox News. A second explanation isbased on rational learning. To the extent that voters are initiallyuncertain about the bias of Fox News, exposure will have a(temporary) effect on beliefs and voting. Voters attribute thepositive coverage of George W. Bush in 2000 partly to Republican
bias of the media source (Fox News) but partly also to highquality of the Republican candidate (Bush). By the year 2000,
however, the conservative slant of Fox News should have beenclear. 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 formedia bias and are subject to nonrational persuasion. In thiscase, exposure to media slant systematically alters beliefs andvoting behavior. In the working paper version [DellaVigna andKaplan 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 bytheir advice. Malmendier and Shanthikumar [forthcoming] showthat small investors follow the recommendations of affiliatedanalysts, 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.

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1191

market expansions on voter turnout. Expansions of The New YorkTimes 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 inthese 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 voters, an implicit assumption underlying most of these papers.
The remainder of the paper is structured as follows. In Section 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 thispaper 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 DATAFox News History and Content. In March of 1996, Rupert
Murdoch announced the introduction of a twenty-four-hour-aday cable news channel, Fox News. Prior to the launch of Fox
News, news broadcasts took up a small share of programmingof the Fox Broadcasting Corporation, which included channels
like Fox Entertainment and the Fox Family Channel. There
was no national news broadcast, and prime time programmingon the Fox channels did not include news.
The political coverage of Fox News is to the right of thecoverage of the other main television news sources, the major
networks—ABC, CBS, and NCB—and CNN. Groseclose and Milyo [2005], for example, compute an index of political orientationof news programs using citations of think tanks. They estimatethat Fox News Special Report is significantly to the right of theother mainstream television media (ABC, CBS, CNN, and NBC).
The news coverage of Fox News is also estimated to be to the rightof the average U. S. elected official.
The distribution of Fox News started on October 7, 1996, in a

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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 companies. In addition, cable companies face a technological constraint
on the number of channels. News channels like Fox News have toconvince local cable companies to be added, often at the expenseof 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 acquired 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 agreement 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 thatare affiliates of Fox Broadcasting. However, the twenty-four-hourchannel is only available via cable and to twelve million satellite
subscribers (in 2000).2
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 theremaining towns, Fox News was available to 34.3 percent of the
population of these states.
Fox News Audience. We document the Fox News penetrationand the composition of the Fox News audience using microlevel
data from Scarborough Research. Scarborough uses a representative panel of households to collect demographic variables andtwo audience measures for each TV channel surveyed. The firstand more inclusive audience measure, the recall measure, is theshare of respondents who answer yes to the question on whether
they watched a given channel in the past seven days. The secondand more restrictive measure, the diary measure, is tabulated
from a week-long diary of TV watching and is the share of respondents who watched a channel for at least one full half-anhour 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).

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1193

In column (1) of Table I, we report summary statistics for the105,201 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 diaryaudience is not available for this sample. We also present summary statistics for the Fox News audience (column (2)) and for the
rest of the sample (column (3)). The education level and unemployment 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 audience 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 nonFox News audience, 26.2 percent identify as Republican and 32.4
percent as Democrat. Fox News viewers therefore are more likely
to be Republican.3 Since the audience data are from 2000, after
the entry of Fox News, this difference could be due either tosorting to Republicans into the Fox News audience or to a persuasion 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 codeof residence and the diary audience measure are both available. This
sample was recorded between February 2000 and August 2001 in
five geographical areas.4 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 toestimate the impact of Fox News availability via cable on the Fox
News audience. This sample (column (4)) is similar to the wholesample (column (1)) both with respect to the measure of the Fox
News recall audience and with respect to demographics, except for ahigher share of Hispanic viewers. The diary audience is three to fivetimes 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).

Unemployment

Hispanic

African American

College graduate

Cable variables
Fox News(recall audience)
Fox News(diary audience)
CNN(recall audience)
CNN(diary audience)
Demographic variables
Some college

Sample1

0.619(0.486)0.219(0.414)0.356(0.479)0.111(0.314)0.081(0.273)0.018(0.134)0.341(0.474)0.214(0.410)0.344(0.475)0.097(0.296)0.107(0.309)0.022(0.147)(2)

Fox News
recall audience

0.173(0.379)(1)

All

All survey respondents

0.213(0.410)0.341(0.474)0.094(0.292)0.112(0.315)0.023(0.149)0.283(0.451)

0(3)

Fox News
non-audience

0.215(0.411)
0.386(0.487)0.084(0.277)0.180(0.384)0.023(0.151)0.166*(0.372)0.035(0.185)0.353*(0.478)0.103(0.304)(4)

All

Summary statistics

0.206(0.405)0.452(0.498)0.020(0.140)0.094(0.293)0.005(0.070)0.603*(0.490)0.350(0.478)0.591*(0.493)
1(5)

Fox News
diary audience

0.215(0.411)0.384(0.486)0.086(0.281)0.183(0.387)0.024(0.153)0.341*(0.474)0.094(0.292)0.146*(0.353)0(6)

Fox News
non-audience

Matched zip-coded subsample

TABLE ISUMMARY STATISTICS ON FOX NEWS AUDIENCE (SCARBOROUGH DATA)

1194
QUARTERLY JOURNAL OF ECONOMICS

0.784(0.411)0.138(0.344)N ⫽ 18,223

N ⫽ 105,201

0.375(0.484)0.294(0.455)0.769(0.421)49.744(16.995)
0.481(0.500)(2)

0.687(0.464)0.147(0.354)0.282(0.450)0.319(0.466)0.693(0.461)45.679(16.633)
0.424(0.494)(1)

Fox News
recall audienceN ⫽ 86,968

0.666(0.471)0.149(0.356)0.262(0.440)0.324(0.468)0.677(0.468)44.827(16.429)
0.412(0.492)(3)

Fox News
non-audienceN ⫽ 11,388

0.754(0.431)0.104(0.305)0.267(0.442)0.335(0.472)0.677(0.468)44.506(16.443)
0.427(0.495)(4)AllN ⫽ 403

0.886(0.318)0.122(0.327)0.536(0.499)0.159(0.366)0.819(0.386)51.727(16.362)0.526(0.500)(5)

Fox News
diary audienceN ⫽ 10,985

0.749(0.434)0.103(0.304)0.257(0.437)0.342(0.474)0.672(0.470)44.241(16.386)
0.423(0.494)(6)

Fox News
non-audience

Matched zip-coded subsample

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)) andin 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 inthe 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 sevendays. 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 (regularaudience).

No. observations

Satellite

Subscriptions
Cable

Voter turnout

Democrat

Political variables
Republican

Male

Age

SampleAll

All survey respondents

Summary statistics

TABLE I(CONTINUED)

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

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QUARTERLY JOURNAL OF ECONOMICS

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 audienceand 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 andthat African Americans are less likely to watch Fox News according 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 information 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, theRecord of American Democracy (ROAD) Project [King et al. 1997]
for the year 1988, and the Atlas Election data [Leip 2004] for the2004 presidential election.
We aggregate the voting information to the town level. A firstgroup 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, Minnesota, Michigan, Montana, Ohio, Pennsylvania, Wisconsin, andWyoming—provide precinct-level voting information with corresponding 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 eliminationof numbers and commonly used words, such as “School” andTHE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1197“Retirement Hm.” 5 We then aggregate the voting data over precincts 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 generates 26,710 distinct localities.
For the twenty-eight U. S. states in our sample, we collectdemographics from the 2000 and the 1990 Census at the level of“Place,” including “Remainders of Place.” We transform the placename 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 thestate, 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 thesetowns, 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, cableofferings are typically limited to the reprogramming of local cablechannels. Their news programming, therefore, is not comparable
to the programming of the other towns.6 Finally, we drop 257
towns with likely voting data problems: 238 towns for which thenumber of precincts generating the town-level vote count differs
by more than 20 percent between 1996 and 2000;7 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 imperfectmatching 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 unmatchedtowns are more likely to be small and rural. The final sample

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

Unemployed

Hispanic

African American

College

Some college

Census variables for 2000
Population

Log turnout in 2000

Log turnout in 1996

Rep. vote share in 2000

Voting variables
Rep. vote share in 1996

Potential subscribers

Cable variables
Number of channels

9,612(32,661)0.257(0.064)0.195(0.133)0.033(0.095)0.031(0.073)0.051(0.035)0.470(0.125)0.538(0.130)⫺0.583(0.481)⫺0.522(0.491)
11,516(32,427)0.259(0.063)0.220(0.147)0.031(0.082)0.035(0.072)0.051(0.035)0.479(0.125)0.538(0.129)⫺0.583(0.482)⫺0.525(0.497)44.52(15.98)
163,622(246,661)

(2)

(1)

28.60
(14.64)
78,124(149,015)

Fox News
in 2000

All towns

All sample

9,150(32,703)
0.257(0.064)0.189(0.129)0.034(0.098)0.030(0.073)0.052(0.035)0.467(0.125)0.538(0.130)⫺0.583(0.480)⫺0.521(0.490)24.73(11.31)
57,384(103,131)(3)

No Fox in
2000

10,564(31,000)
0.258(0.064)0.216(0.145)0.028(0.073)0.032(0.067)0.051(0.035)0.482(0.124)0.541(0.128)⫺0.583(0.471)⫺0.525(0.487)44.39(16.14)140,457(198,871)(4)Fox News
in 2000

7,157(23,261)0.257(0.066)0.178(0.118)0.027(0.083)0.027(0.065)0.052(0.035)0.475(0.124)0.550(0.126)⫺0.578(0.732)⫺0.518(0.483)24.41(11.57)47,373(91,025)(5)

No Fox in
2000

Mixed districts

TABLE IISUMMARY STATISTICS ON CABLE AND ELECTION DATA

11,872(33,678)
0.258(0.063)0.224(0.150)0.030(0.084)0.035(0.074)0.050(0.036)0.477(0.125)0.533(0.129)⫺0.573(0.434)⫺0.510(0.449)45.00(16.06)167,006(254,926)(6)

Fox News
in 2000

12,266(37,678)
0.254(0.067)0.210(0.146)0.026(0.072)0.041(0.096)0.053(0.038)0.475(0.127)0.536(0.133)⫺0.566(0.418)⫺0.504(0.431)

26.05(11.81)
70,832(116,337)(7)

No Fox in
2000

Mixed counties

1198
QUARTERLY JOURNAL OF ECONOMICS

N ⫽ 9,256

N ⫽ 1,807

N ⫽ 7,449

687(3,375)0.041(0.049)0.036(0.042)0.004(0.026)0.010(0.025)⫺0.013(0.039)0.083(0.238)772(3,775)0.035(0.046)0.041(0.044)0.003(0.025)0.013(0.030)⫺0.011(0.037)0.079(0.239)N ⫽ 1,734

681(3,499)0.036(0.046)0.041(0.045)0.003(0.024)0.012(0.027)⫺0.011(0.037)0.082(0.241)0.518(0.446)(4)

Fox News
in 2000

N ⫽ 5,897

584(2,727)0.044(0.049)0.035(0.041)
0.003(0.024)0.010(0.025)⫺0.013(0.040)0.080(0.240)0.331(0.416)(5)

No Fox in
2000

Mixed districts

N ⫽ 1,548

805(3,974)0.035(0.046)0.042(0.045)0.003(0.024)0.013(0.029)⫺0.012(0.038)0.084(0.247)0.556(0.446)(6)

Fox News
in 2000

N ⫽ 2,342

934(4,461)
0.034(0.047)0.041(0.043)0.004(0.024)0.011(0.028)⫺0.012(0.036)0.086(0.242)0.441(0.447)(7)

No Fox in
2000

Mixed counties

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 townthat 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 bya 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 Republicanand 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.

No. of observations

0.374(0.429)(3)

No Fox in
2000

0.537
(0.447)

(2)

(1)

0.406
(0.438)
Census variables, change from 1990 to 2000:
Population
704(3,457)
Some college
0.040(0.048)
College
0.037(0.042)African American
0.004(0.026)
Hispanic
0.011(0.026)
Unemployed⫺0.012(0.038)Urban
0.082(0.238)Urban

Fox News
in 2000

All towns

All sample

TABLE II(CONTINUED)

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

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QUARTERLY JOURNAL OF ECONOMICS

covers 65.9 percent of the population and 68.6 percent of total
votes cast for the twenty-eight states in the year 2000.8
Summary Statistics. Table II presents unweighted summary
statistics on the cable and election data. The average cable system in the year 2000 included twenty-eight channels in the Basicand 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, andthe share of the town that is urban (shown in Table II). We also
include the share of high school graduates, the share of males, themarriage rate, the employment rate, and average income (notshown in Table II).
We compare towns that offered Fox News in their programming (column (2)) and towns that did not (column (3)). Towns thatoffer Fox News have a substantially higher number of channels
offered (44.5 versus 24.7), are 25 percent larger, are served bycable 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 thosethat did not offer Fox News increased theirs by an even larger 7.1
percentage points (from 46.7 to 53.8 percent). These figures suggest a perverse Fox News effect. This result, however, does notweight towns by size, nor does it take into account differences
between Fox and non-Fox towns in voting trends across geographical areas, demographic composition, and cable market.
Later, we estimate the Fox News effect, taking into account allthese 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 dropsome of the largest cities like New York, which have several cable systems, someof 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 matching towns. Details on the state-by-state coverage rate is in Appendix Table I in
DellaVigna and Kaplan [2006].

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1201

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 thissubsample. Towns in this subsample (columns (4) and (5) of TableII) 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 (FigureI). 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 theirprogramming in the year 2000 to towns without Fox News. Since
the assignment of towns into these two groups is not random, weinvestigate the nature of the selection and estimate which townlevel variables predict the availability of Fox News in 2000. In
particular, we focus on political variables. Fox News may wellhave 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, theestimated Fox News effect may just be capturing political trends.
FOX
The Fox News variable, d k,2000, equals one if all cable systems in town k in year 2000 include Fox News in either the Basic
package or one of the Expanded Basic packages, and zero if nocable system includes Fox News. We estimate a linear probability
model9:(1)

FOX
R,PresPres⬘
d k,2000⫽ ␣ ⫹ ␤vk,1996⫹ ␤T tk,1996⫹ ⌫2000 Xk,2000⫹ ⌫00–90 Xk,00–90 ⫹ ⌫C Ck,2000 ⫹ εk .
The pre-Fox News political variables from the 1996 presidential
R,Preselections are the two-party Republican vote share, v k,1996, andthe voter turnout measured by log of votes cast as share ofPres⬘
population, t k,1996. The demographic variables are X k,2000 , the9. The results are similar with logit and conditional logit specifications.

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

1202
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THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1203

set of controls from the 2000 Census, and X k,2000–1990 , the set ofchanges in controls between the 1990 Census and the 2000 Census (see Table II). Finally, the controls for features of the cablesystem are C k,2000 , deciles in the number of channels provided
and in the number of potential subscribers. To ensure that theresults are representative of the average voter, and since the
R,Presprecision of the vote share variable v k,1996
is increasing in thenumber of votes cast, we weight the observations by votes cast in
1996.10 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 positively correlated with town turnout, but not with Republican voteshare. As we add demographic controls (column (2)), the latter
result changes. Fox News availability in 2000 is substantiallyhigher 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 thesetowns are less likely to be Republican, adding demographics
variables in column (2) raises the coefficient on Republican voteshare. Next, we add the controls C k,2000 for cable system features(column (3)), raising the R2 to 0.4093; larger cable systems are much
more likely to offer Fox News. Controlling for cable system features
lowers the coefficient ␤ˆ on the Republican vote share by half.
In column (4), we add congressional district fixed effects.
With these additional geographic controls, specification (1) captures the determinants of within-district Fox News availability,
conditional on demographic and cable controls. (The coefficientson the controls are reported in Appendix II). In this specification,
there is no evidence that towns with higher Republican voteshare are more likely to offer Fox News; in fact, the estimated ␤ˆ ⫽⫺.0343 is negative, albeit insignificant. Similarly, the turnout
coefficient is small and insignificant. Given the precision of theestimates, we can reject substantial effects of pre-existing political composition on the availability of Fox News, conditional on thecontrol variables. Moreover, we cannot reject the joint test thatthe 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.

X
—
—
—
F ⫽ 3.54***0.0902N ⫽ 9,256—

0.0281N ⫽ 9,256

0.6363(0.2101)***0.0909(0.0348)***

(2)

—
—
—

0.1436(0.1549)
0.1101(0.0557)**(1)—
F ⫽ 2.73***F ⫽ 18.08***0.4093N ⫽ 9,256

X
X—

0.3902(0.1566)**
0.0656(0.0278)**(3)—
F ⫽ 1.11
F ⫽ 21.09***
0.6698N ⫽ 9,256

X
F ⫽ 1.28
F ⫽ 18.61***
0.7683N ⫽ 9,256

X
X—⫺0.0442(0.1024)⫺0.0053(0.0173)⫺0.0343(0.0937)0.0139(0.0124)

X
X
X

(5)

(4)

—
F ⫽ 1.57**
F ⫽ 8.19***
0.6313N ⫽ 3,722

X
X
X

0.0902(0.1321)0.0286(0.0234)
0.214(0.2481)(6)

X
F ⫽ 1.31
F ⫽ 8.75***
0.7622N ⫽ 3,722

X
X—

0.0627(0.1333)
0.0257(0.0258)⫺0.2548(0.2345)(7)

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 arelisted 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.

Pres. Rep. vote share change
1998–1992
Control variables
Census controls: 1990 and 2000
Cable system controls
U. S. House district fixed
effects
County fixed effects
F-test: Census controls ⫽ 0
F-test: Cable controls ⫽ 0
R2
NPres. republican vote share in
1996
Pres. log turnout in 1996

Dep. var.

Availability of Fox News via cable in 2000

TABLE III
DETERMINANTS OF FOX NEWS AVAILABILITY, LINEAR PROBABILITY MODEL

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THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1205

system, availability of Fox News in 2000 is therefore uncorrelatedwith both political outcomes and demographics. We obtain similar
results when we introduce county fixed effects instead of congressional district fixed effects (column (5)). Our interpretation ofthese results is that, while overall the availability of Fox News ishighly selective—Fox News enters into larger markets and, given
town size, into more Republican areas— conditional on cable market 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 between 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 between the two specifications.
Overall, Fox News in 2000 selected primarily into cable system with a large number of channels, as well as into specificcounties 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 politicaltrends 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
FOXby the year 2000 (d k,2000⫽ 1) with towns where Fox News wasFOX
not available by the year 2000 (d k,2000⫽ 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 thetiming 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 November 2000 elections, Fox News had an audience that was
smaller, but nonetheless comparable to that of CNN. Our baseline specification is(2)

R,Pres
R,PresFOX⫺ vk,1996⫽ ␣ ⫹ ␤F dk,2000⫹ ⌫2000 Xk,2000
v k,2000⫹ ⌫00–90 Xk,00–90 ⫹ ⌫C Ck,2000 ⫹ εk .

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As in Table III, we control for town-level demographics in levels(X 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 thestandard errors are clustered at the level of the local cable
company.
We first implement a simple difference-in-difference estimator and estimate (2) without controls (⌫2000 ⫽ ⌫00 –90 ⫽ 0 and ⌫ C ⫽0) (column (1) in Table IV). On average, in our sample the voteshare for Republicans increased by 3.47 percentage points (␣ˆ ⫽0.0347) between the 1996 and the 2000 elections. Compared tothis overall increase, towns with Fox News became (insignificantly) less Republican by two-tenths of a percentage point (␤ˆ F ⫽⫺.0025) relative to towns without Fox News. The standard error(0.0037), however, is sufficiently large that we cannot rule outthat the entry of Fox News increased the Republican vote shareby half a percentage point. In column (2), we add demographic
controls, raising the R 2 of the regression from 0.0007 to 0.5207.
The estimate for ␤ F , ␤ˆ F ⫽ 0.0027, becomes positive but is stillinsignificant. In column (3), we add controls for cable size C k,2000 ,rendering the Fox News coefficient positive and significant (␤ˆ F ⫽0.008). Introducing control variables increases the point estimate of ␤ F , suggesting that the unobservables bias the estimateof the Fox News effect downward.
In the two benchmark specifications we include district fixed
effects (column (4)) and county fixed effects (column (5)) in addition to the full set of controls. (The coefficients on the controls forthe specification in column (4) are reported in Appendix II.) These
specifications control for unobserved trends in voting that arecommon to a geographic area, and that may be correlated with
Fox News availability. The identification of ␤ F depends on thecomparison of neighboring towns with and without Fox News.
The key advantage of specifications with cable, demographic, andgeographic controls is that, conditional on these variables, theavailability of Fox News is uncorrelated with political variables(Table III). The estimate of the effect of Fox News is positive andsignificant 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, availability of Fox News increases the Republican vote share by four- toseven-tenths of a percentage point, a sizeable and precisely estimated effect.
In columns (6) and (7), we replicate the benchmark results

X
—
—
—
0.5207N ⫽ 9,256—
0.0007N ⫽ 9,256⫺0.028(0.0245)0.0027(0.0024)

(2)

—
—
—

0.0347(0.0017)***⫺0.0025(0.0037)(1)—
0.5573N ⫽ 9,256

X
X—⫺0.0255(0.0236)0.008(0.0026)***(3)—0.7533N ⫽ 9,256

X
X
X

0.0116(0.0154)0.0042(0.0015)***(4)X
0.8119N ⫽ 9,256

X
X—

0.0253(0.0185)

0.0069(0.0014)***(5)—0.7528N ⫽ 3,722

X
X
X

0.0037(0.0021)*0.0229(0.0216)⫺0.0377(0.0258)(6)

X
0.8244N ⫽ 3,722

X
X—

0.0048(0.0019)**0.0514(0.0219)**0.0081(0.0313)(7)

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 forthe 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 the2000 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.

Control variables
Census controls: 1990 and 2000
Cable system controls
U. S. House district fixed
effects
County fixed effects
R2
N

Availability of Fox News via
cable in 2000
Pres. Rep. vote share change
1988–1992
Constant

Dep. var.

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

TABLE IVTHE EFFECT OF FOX NEWS ON THE 2000 –1996 PRESIDENTIAL VOTE SHARE CHANGE
THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

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after adding the change in the Republican vote share between
1988 and 1992 as an additional control. Over this substantiallysmaller sample (3,722 observations), the effect of Fox News availability is less precisely estimated and somewhat smaller but still
significant in the specification with county fixed effects.11 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 theresults to alternative ways of coding the dependent variable (thevote 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 nexttables we present the results for the specifications with U. S.
House District fixed effects; the results are similar for the specifications with County fixed effects.
First, the results are robust to controlling for the vote sharein 1996 instead of using the vote share change between 2000 and1996 (column (1)). The results are also robust to using the allparty vote share (column (2)), an alternative measure that controls for third-party effects.
Second, we also consider an alternative specification of exposure to Fox News, the ratio of the number of Fox News subscribers 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 estimation methods. In column (3) we show that restricting thesample to the states with a high proportion of correctly matchedelection data12 yields, if anything, a higher effect of Fox News
entry. We also show (column (4)) that the largest cities are notdriving the estimates: the results are similar to the benchmark
results when we run an unweighted regression on medium- andlarge-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 thissample when we do not control for trends.
12. We exclude states in which the election data in the final sample cover lessthan 50 percent of the total votes cast in the state in either 1996 or 2000. Thiseliminates all states in which the town names are obtained from the precinct
names, possibly generating erroneous matches with the cable data.

X
X
X
—
—
—
0.827
N ⫽ 9,256

0.004(0.0016)**

(2)

(4)

(5)

X
X
X
X
—
—
0.7556N ⫽ 7,758

X
X
X
—
X
—
0.7369N ⫽ 3,241

X
X
X
—
—
X
—
N ⫽ 9,2560.00480.00410.0047(0.0016)*** (0.0017)*** (0.0016)***(3)

Two-party vote share

X
X
X
—
—
—
0.6281N ⫽ 8,605

0.0021(0.0020)(6)

Persistence Pres.
Rep. vote share
2004–2000

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 sharefor 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 bothin 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 ineither 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 estimateof 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.

Control variables
Census controls: 1990 and 2000
Cable system controls
U. S. House district fixed effects
Election data with high coverage
Unweighted, turnout ⬎ 2000
Nearest-neighbor matching, unweighted
R2
N
X
X
X
—
—
—
0.9824N ⫽ 9,2560.0041(0.0016)***
0.9362(0.0079)***Availability of Fox News via cable in 2000

Republican vote share in 1996

(1)

Dep. var.

Rep. two-party
All-party
vote share in 2000 vote share

Pres. Rep. vote share change 2000–1996

Robustness

TABLE VTHE FOX NEWS EFFECT: ROBUSTNESS AND PERSISTENCETHE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

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at least 2,000 votes). In Section III.C, we show that the estimatedeffects are instead smaller in small, mostly rural towns.
To check the robustness of our OLS results, we present theresults of a simple matching procedure, nearest-neighbor matching [Abadie et al. 2001]. Each town with Fox News (treatmenttown) 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 findings. Finally, the results are also robust to adopting the optimal
trimming approach of Crump et al. [2005], which focuses theanalysis 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 percentage point vote share increase between 2000 and 2004. The
effect of Fox News therefore appears to be persistent, if notincreasing over time. Persistence is consistent with the predictions of a model of nonrational persuasion; however, this result
could also be due to greater audience in Fox News areas over the2000 –2004 period.
Comparison with Earlier Results. We now reconcile the findings 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 thecurrent specification preferable. In Appendix III, we introduce inthree successive steps the earlier specification and show that,while each of the factors mattered, the first two made the mostdifference. The estimates of the Fox News effect are 0.3 percentage points lower (0.0014 and 0.0040) if we run unweighted regressions (columns (1) and (2)). The effect is still significant withcounty fixed effects but not with district fixed effects. The lower
point estimates are likely due to smaller treatment effects insmall, more rural towns (see Section III.C) and possibly to higher
measurement error in very small towns. Regressions weighted byturnout better represent the impact of Fox News on the average
voter.
In columns (3) and (4), in addition to running unweighted

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1211

regressions, we also include observations that are likely measured 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 exclude 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 impactof 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 (columns (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 sharebetween 1996 and 2000? The average weighted change in voteshare 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 thatFox News is likely to have shifted. We assume a treatment effectof Fox News of 0.55 percentage points, the midpoint of the benchmark estimates, and a diffusion of Fox News of 34 percent of the
population, also for the twenty-two states for which we do nothave 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 percentage points. Assuming that Fox News did not affect turnout substantially, Fox News shifted approximately 200,000 votes fromthe Democratic candidate to the Republican candidate.
We also predict the number of votes shifted by Fox News inFlorida, the pivotal state in the 2000 U. S. presidential election.

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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 thanBush’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 theBush victory in the unusually close election. Moreover, this impact may become larger over time as the Fox News audience anddiffusion grows.
III.C. Interactions
In Table VI, we examine how the Fox News effect interacts
with town characteristics, namely the number of channels, theshare of the population that is urban, and the political orientationof the district. We split congressional districts into thirds by the2000 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 reporting (though CNN and the network news are available in all towns
in the sample) or merely lower audience rates for Fox News whenmore channels are available.
Second, we find that the impact of Fox News is (marginallysignificantly) larger in urban towns and lower in the Republican
districts, significantly so with county fixed effects. Both of theseresults may be explained by the fact that in rural towns and in
Republican Districts most people already voted Republican, andtherefore, 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 asmaller at-risk population.
III.D. Placebos
We exploit the timing of the Fox News entry to constructplacebo treatments. The first placebo treatment (column (3) in

X
X
X
—
0.754
N ⫽ 9,256⫺0.0019(0.0008)**
0.004(0.0023)*⫺0.0043(0.0030)⫺0.0028(0.0027)0.0109(0.0042)***

(1)

X
X
—
X
0.8124N ⫽ 9,256⫺0.0013(0.0008)
0.0033(0.0020)*⫺0.0004(0.0023)⫺0.0064(0.0024)***0.0105(0.0039)***

(2)

X
X
X
—
0.7523N ⫽ 8,645

0.0036(0.0016)**⫺0.0001(0.0012)

(3)

X
X
X
—
0.6517N ⫽ 3,722

0.0026(0.0026)⫺0.0024(0.0031)

X
X
X—
0.6197N ⫽ 4,006

(5)

(4)

1992–1988

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 Newswas 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 inAppendix 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 the2000 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.

Control variables:
Census controls: 1990 and 2000
Cable system controls
U. S. House district fixed effects
County fixed effects
R2
N

Fox News in 2000* (Republican district)

Fox News in 2000* (swing district)

Fox News in 2000* (urban in 2000)

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

Availability of Fox News via cable in 2003

Availability of Fox News via cable in 2000

Dep. var.

1996–1992

Presidential Republican vote share
2000–1996

Presid. Rep. vote share
2000–1996

Placebo specifications

Interactions

TABLE VITHE FOX NEWS EFFECT: INTERACTIONS AND PLACEBO SPECIFICATIONSTHE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1213

1214

QUARTERLY JOURNAL OF ECONOMICS

Table VI) uses data on Fox News diffusion in 2003. In 2003, Fox
News was available in 4,844 out of 8,645 towns.13 The introduction 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 noeffect on voting.
In a second set of placebo treatments, we estimate whether
the introduction of Fox News in 2000 predicts the vote sharechange between 1992 and 1996 (column (4)) or between 1988 and1992 (column (5)). Obviously, Fox News introduction in 2000
should not affect voting between years in which Fox News did notexist. We find no evidence of a significant correlation in either
time period. Voting trends are unlikely to be responsible for theFox News effect.
III.E. Voter Turnout
The significant impact of Fox News on the Republican voteshare could occur for two reasons. First, Fox News entry convinced Democratic voters to vote Republican. Second, Fox News
attracted new Republican voters. We use measures of turnout totest these hypotheses.
The baseline regression for voter turnout is
(3)

Pres
Pres
FOX
tk,2000⫺ tk,1996⫽ ␣ ⫹ ␤F dk,2000⫹ ␥关ln 共Popk,2000 兲⫺ ln 共Popk,1996 兲兴 ⫹ ⌫2000 Xk,2000 ⫹ ⌫00–90 Xk,00–90 ⫹ ⌫C Ck,2000 ⫹ εk ,
Pres
Pres
is the log total votes in town k in year t: t k,t⫽where t k,tTOT,Presln (V k,t). The change in this measure over time is the percent change in total votes cast. This specification controls for thepercentage change in the voting-age town population over time,ln (Popk,2000 ) ⫺ ln (Popk,1996 ) since increases in population
would naturally increase the number of votes cast.
Columns (1)–(3) in Table VII show the results. The averagechange in log votes is 0.0869, implying an 8.69 percent higher
turnout in the much tighter presidential race of 2000. The estimate for ␤ F is positive but insignificant with district fixed effects
and is large and significant with county fixed effects. This second
estimate (␤ˆ F ⫽ 0.0178) suggests that Fox News increased turnout by 1.78 percent, a large effect. In both specifications, the13. 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.

X
X
X
—
0.9768N ⫽ 8,192

0.0039(0.0067)
0.8295(0.0111)***0.0072(0.0026)***

(4)

X
X
—
X
0.9829N ⫽ 8,192⫺0.0017(0.0060)
0.8432(0.0146)***0.0071(0.0028)**

(5)

X
X
X
—
0.9768N ⫽ 8,192

0.0033(0.0067)
0.8289(0.1111)***⫺0.0042(0.0047)⫺0.0075(0.0054)0.01(0.0035)***(6)

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 datafor 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 sharein 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 thetown’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 the2000 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.

Fox News in 2000* (swing district)

X
X
X
—
0.658
N ⫽ 9,2560.0147(0.0061)**
0.3641(0.0425)***(3)

Control variables
Census controls: 1990 and 2000
Cable system controls
U. S. House district fixed effects
County fixed effects
2
R
N
X
X
—
X
0.6863N ⫽ 9,256

0.0178(0.0051)***0.3707(0.0440)***(2)

Fox News in 2000* (Republican district)
X
X
X—
0.6151N ⫽ 9,2560.0046(0.0039)0.3655(0.0427)***(1)

Republican vote share in 2000 senatorial
elections

Change in log (total votes cast) between
2000 and 1996 pres. elections⫺0.0207(0.0087)*⫺0.0177(0.0090)**

Republican vote share in 1996 presidential elections

Fox News in 2000* (New York race)

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

Availability of Fox News via cable in 2000

Dep. var.

Senatorial elections

Turnout (presidential elections)

TABLE VII
FOX NEWS AND OTHER POLITICAL OUTCOMES: TURNOUT AND SENATORIAL ELECTIONSTHE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1215

1216

QUARTERLY JOURNAL OF ECONOMICS

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 findingthat the impact of Fox News on vote share is larger in the more
Democratic areas, this suggests that the main effect of Fox Newswas to induce nonvoters in Democratic districts to turn out andvote Republican.
Overall, Fox News entry into a market appears to havemobilized new voters, especially in Democratic districts. However, the evidence is not as consistent as for the effect on voteshare.
III.F. Senate Elections
The previous findings suggest that Fox News had a significant effect on the Republican vote share and on turnout in thepresidential election. In this section, we consider whether theeffect 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 alarge majority of Senate races fail to get national coverage. Theseelections 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, almost like presidential races. This allows us to compare the effectof Fox News on races that were not covered, where only ideological 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 Clinton.14 All the other Senate candidates running in the 2000 campaign combined got a total of seventy-three mentions, with Joe
Lieberman, who was typically mentioned because of his vicepresidential 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 somehonesty issues about campaign finance, but they pale beside the deceit factory the
Clintons have set up.”

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1217

Senate elections and whether it had a differential effect for the
Clinton–Lazio race. We denote by d NY the indicator variable for
the New York Senate races. We estimate the specification
(4)

R,Sen
R,PresFOXFOXv k,2000⫽ ␣ ⫹ ␣P vk,1996⫹ ␤F dk,2000⫹ ␾F dk,2000
ⴱ dNY⫹ ⌫2000 Xk,2000 ⫹ ⌫00–90 Xk,00–90 ⫹ ⌫C Ck,2000 ⫹ εk ,where ␤ F indicates the effect of Fox News on Senate races otherthan New York and ␾ F indicates the differential effect for thefeatured New York race. This specification controls for the 1996
presidential vote share.15
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 standard errors on the coefficient ␾ˆ F are relatively large. We then testfor heterogeneity by political areas (column (6)). Consistent withthe 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 effectfor 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 theshare 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 shareinstead [see DellaVigna and Kaplan 2006]. The disadvantage of this specificationis that it restricts the sample to 2,037 towns in five states.

1218

QUARTERLY JOURNAL OF ECONOMICSr 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 theshare of nonvoters. Since the two types of towns have similar
political outcomes in the pre-Fox News period conditional on a setof controls (Tables II and III), we assume that r and d are thesame 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 treatment towns; that is, e T ⬎ e C ⱖ 0. We allow nonzero exposure e C
in control towns because, for example, of the availability of satellite which broadcasts Fox News to subscribers in both towns.
For simplicity, we also assume that the exposure e j to Fox Newsin town j is independent of political affiliation. That is, we assume
that Republicans are as likely as Democrats or nonvoters towatch Fox News when available. While Republicans are more
likely to watch Fox News (Table I), we cannot rule out that thiscaptures the causal convincing effect of Fox News, rather thandifferential exposure e j by party.
The key parameter is f, the fraction of the audience that isconvinced 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 j , where j ⫽ T, C.
Therefore, the introduction of Fox News increases the fraction
voting Republican by (1 ⫺ r)e j f. The two-party vote share v j intown j, with j ⫽ T, C, equals
(5)

vj ⫽

r ⫹ 共1 ⫺ r兲e j f.
r ⫹ d ⫹ 共1 ⫺ r ⫺ d兲e j f(Turnout increases since Fox News induces a fraction f of thenonvoters to vote Republican.) Using expression (5), we solve forthe difference in vote share between treatment and control towns,
v T ⫺ v C , the equivalent of ␤ˆ F in the data. We obtain v T ⫺ v C ⫽(e T ⫺ e C ) fd/t C t T , where t j ⬅ (r ⫹ d ⫹ (1 ⫺ r ⫺ d)ej f) is theturnout in town j. The implied persuasion rate f is(6)

f⫽

共1 ⫺ r兲t C t T
vT ⫺ vC.
共e T ⫺ e C兲共1 ⫺ r兲d

The first term in expression (6) is the influence rate pertreated population, and the second term is a factor correcting forturnout effects. The numerator of the first term, v T ⫺ v C , is theTHE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1219

shift in Republican vote share due to the availability of Fox News
via cable. The denominator, (e T ⫺ e C )(1 ⫺ r), normalizes thisvote 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 avote but only in the first case does the Democratic party lose avote. The larger the ratio of non-Republicans (1 ⫺ r) to Democrats d, hence, the bigger is the convincing impact for a given voteshare change. In addition, the term t C t T corrects for the fact thata higher turnout t j increases the denominator of expression (5),and, therefore, decreases the impact of f on v j .
Audience Data. We estimate the differential exposure (e T ⫺e C ) in expression (6) using the microlevel Scarborough data on
television audiences described in Section II. We use the subsample of 11,388 respondents for whom we observe the zip code ofresidence and for whom we can match by zip code to the cabledata 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 thespecifications in the rest of the paper. For each town k of the 568
towns in this sample, e kFOX is the fraction of town residents in theFox News audience. We estimateFOX⫹ ⌫2000 Xk,2000(7) e kFOX ⫽ ␣ ⫹ ␤F dk,2000⫹ ⌫00–90 Xk,00–90 ⫹ ⌫C Ck,2000 ⫹ εk .
The regression is weighted by the number of respondents in atown, and the standard errors are clustered at the level of thelocal cable company. The coefficient ␤ F 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 (␤ˆ F ⫽ 0.0270) additional town residents to watch Fox
News for at least a full half hour per week. The estimate issignificant and sizeable. In towns where Fox News is not available via cable, 2.62 percent (␣ˆ ⫽ 0.262) of the residents still watch

0.0827(0.0298)***0.2829(0.1020)***0.3507N ⫽ 568

0.0339(0.0151)**
0.1162(0.0518)**
0.3105N ⫽ 568

0.0655N ⫽ 568

0.3148N ⫽ 545

X
X
X—

0.0346(0.0116)***0.0016(0.0090)0.1317(0.1102)(4)

0.0217N ⫽ 568————

0.0947(0.0054)***0.0251(0.0121)**(5)0.3872N ⫽ 568

X
X
X—

0.7213(0.1674)***0.0042(0.0114)(6)

Watched CNN

0.4262N ⫽ 568

X
X—
X

0.0917(0.2119)0.0045(0.0104)(7)

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 ratioof 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 ofchannels 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.

X
X
—
X

X
X
X
—

⫺0.0531(0.1316)0.0251(0.0082)***

(3)

—
—
—
—

0.0928(0.1046)

0.0262(0.0036)***

Control variables
Census controls: 1990 and 2000
Cable system controls
U. S. House district fixed effects
County fixed effects
2SLS estimates of persuasion rates
Estimates using (predicted)
recall audience measure
Estimates using diary audiencemeasureR2
N

0.0371(0.0105)***0.027(0.0058)***Availability of Fox News via cablein 2000
Availability of Fox News via cablein 2003
Constant(2)(1)

Dep. var.

Watched Fox News

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

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

1220
QUARTERLY JOURNAL OF ECONOMICS

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1221

Fox News for at least a full half hour per week. About half of theFox News audience, therefore, watches Fox News in ways otherthan 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 tounderstate 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 geographic controls used in the body of the paper. The estimateddifferential exposure rates are ␤ˆ F ⫽ 0.0371 with congressional
district fixed effects and ␤ˆ F ⫽ 0.0251 with county fixed effects.
Interestingly, introducing control variables and district fixed effects increases the estimated ␤ˆ F .
As a first placebo test, we show that availability of Fox News
via cable in 2003 does not increase audience rates in 2000 (column (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 T ⫺ e C
as the coefficient ␤ˆ F of columns (2) and (3) in Table VIII. We firstuse the more inclusive recall audience measure. Since we cannot
directly estimate the model (7) for the recall audience variable,
we multiply the estimates of ␤ˆ F 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 ê T ⫺ ê C are 0.1271 with district fixed effects and 0.0860 withcounty fixed effects.
We evaluate the political variables t T , t C , r, and d using thesample averages of the 2000 elections. We weight the averages bytotal votes cast in 2000 to better approximate the individual-level
expressions (5) and (6). The average weighted turnout in 2000 asa 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 ⫽ t C ⫽ 0.560. 16
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.

1222

QUARTERLY JOURNAL OF ECONOMICS

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 T ⫺ v C )/(e T ⫺ e C ).
Combining the estimates of these variables (e T ⫺ e C , t T , t C ,d) with the estimates of the voting impact (v T ⫺ v C ) from Table
IV, we compute persuasion rates f using the (predicted) recall
audience measure. The standard errors for f take into account theuncertainty in both the audience regressions (Table IV) and thevote share regressions (Table VIII).17 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 notalready voting Republican to do so. With county fixed effects, wederive f̂ ⫽ 1.024 ⴱ (0.0069/0.0860) ⫽ 0.0827; that is, Fox News
convinced 8.27 percent of its audience. Both estimates are significantly different from zero, but are fairly imprecisely estimateddue to the small sample of the audience regressions.
In Table VIII we also report the persuasion rates f̂ computedwith respect to the diary audience measure. The persuasion rates
are 3.42 times larger if e F ⫺ e N is measured using the diary dataas the measure of audience. The resulting estimates f̂ ⫽ 0.1162(district fixed effects) and f̂ ⫽ 0.2829 (county fixed effects) imply
large persuasion effects of the media. We summarize these results 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 ofusing weighted means, we use the unweighted means (t ⫽ 0.583
and d ⫽ 0.583 ⴱ (1 ⫺ 0.538)), we obtain f̂ ⫽ 0.0417 with district
fixed effects and f̂ ⫽ 0.1012 with county fixed effects. These
effects are in the ballpark of the benchmark estimates.
The persuasion rate estimates are more sensitive to assumptions about the exposure rate. A factor that leads to higher persuasion rates is the self-selection of Republicans in the Fox News
audience. In Table VIII, we estimate the selective exposure e T ⫺e C 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 ␤ F in the vote share in theaudience regressions (in the sample of towns for which both are available). The
standard errors do not take into account the (limited) uncertainty in the estimateof t T , t C , d, and of the conversion rate.

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1223

in the Fox News audience, this downward biases the estimateof f. 18
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 restrictive 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 literature summarized in Table IX. We discuss field experiments,
laboratory experiments, and surveys.
Field Experiments. In a series of field experiments [Greenand 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 measured using official individual voting records. In other experiments, the randomization is done at the precinct level, and precinct-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 j , forj ⫽ T, C. It follows that t j ⫽ t ⫹ f(1 ⫺ t)e j and t T ⫺ t C ⫽ (1 ⫺t)(e T ⫺ e C ) f. This implies
(8)

f⫽

1
tT ⫺ tC.
e T ⫺ e C 共1 ⫺ t兲In these experiments, e C ⫽ 0 since no one in the control group istreated, hence t ⫽ t C . In Table IX, we summarize the treatment,
election type, year, location, and sample size of five such experiments. Using the turnout rates in the control (t C ) and treatment(t T ) groups and the exposure rate e T ⫺ e C , we compute thepersuasion 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-Republicans, since the party identification variable is measured in 2000 and it captures
the causal effect of Fox News, as well as sorting.

(3)Variable t

Generalelect.
Generalelect.
Governorelect.

Federalelect.
Federalelect.
Local elect.

(5)

Place

0.405
0.291

N ⫽ 4,377

2005 Washington N ⫽ 1,011

Dem. shareof votes

0.660

N ⫽ 4,377

2000 2 cities

0.286

N ⫽ 18,933

Turnout

2001 6 cities

Turnout

0.422

N ⫽ 14,850

2000 4 cities

1998 New Haven

Turnout

0.422

0.556

0.556

(7)

N ⫽ 14,473

N ⫽66,372,804(6)

Sample size

0.363

0.416

0.711

0.310

0.448

0.463

0.563

0.560

(8)

0.940

0.414

0.737

0.293

0.270

0.270

0.086

0.127

(9)

0.109

0.045

0.205

0.118

0.167

0.263

0.083/0.283

0.034/0.116(10)Exposure
Controlrate
Persuasiongroup TreatmenteT ⫺ eCgroup t C
rate
tT

Turnout

1998 New Haven

2000 28 U. S.
states(4)

Year

Turnout

Presidential Republican
election
vote share(1)

Fox News
exposure,
district f.e.
Fox News
exposure,
county f.e.

(2)Treatment

Door-to-door
canvassing
Canvassing ⫹mail ⫹ calls
Green, Gerber, and Door-to-door
Nickerson [2003]
canvassing
Green and GerberPhone calls by[2001]
youth vote
Phone calls 18–
30-year-olds
Free
Gerber, Karlan,
subscription
and Bergan[2006]
to Washington
Post

Field Experiments
Gerber and Green[2000]Fox News Study
DellaVigna andKaplan [2006]

Paper

Electiontype orquestion

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

TABLE IXCOMPARISON WITH PERSUASION RATES IN OTHER MEDIA STUDIES1224
QUARTERLY JOURNAL OF ECONOMICS

Respondentwatches CNN
Respondentwatches Al
JazeeraRespondentwatches Fox
News

(3)

Variable t
(4)

Year
(5)

Place

Did U. S.
find
WMD inIraq?
Did Arabs
do 9/11
attack?
Share of yes
answers

Share of yes
answers

2002 Arabcountries
2002

2003 USA

Governor
Vote share
1990
elect.
for party
Southern
Senatesponsoring 1992
California
elect.
ad
Mayor elect.
1993

(1)

Laboratory
exposure to
30-second
political ad(2)Treatment

0.215
0.215

N⫽2,457

0.220

0.530

(7)

N⫽2,457

N⫽8,634

N⫽1,716(6)

Sample size

0.133

0.280

0.330

0.568

(8)

1.000

1.000

1.000

1.000

(9)

0.105

0.083

0.141

0.082

(10)

Exposure
Controlrate
Persuasiongroup TreatmenteT ⫺ eCgroup t C
rate
tT

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

Gentzkow andShapiro [2004]

Surveys
Kull, Ramsay, andLewis [2003]

Laboratory
Experiments
Ansolabehere andIyengar [1995]

Paper

Electiontype orquestion

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

TABLE IX(CONTINUED)

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1225

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QUARTERLY JOURNAL OF ECONOMICS

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) Democratic voters for exposure to the left-wing newspaper, corresponding to a persuasion rate f of 0.109. (We use expression (8) wheret is the share of Democratic votes out of all survey respondents,
including nonvoters, and where we assume that all recipients ofa subscription read the newspaper.) However, they also find thatthe share of Democratic voters increases after exposure to theright-wing paper, albeit insignificantly.
Laboratory Experiments. Ansolabehere and Iyengar (1995]
expose experimental subjects to thirty-second political advertisements supporting a candidate (or criticizing the opposite candidate). They then elicit beliefs and voting intentions at the end of
the experiment. In Table IX we summarize the findings for threesets of experiments with 1,716 total subjects. On average, exposure 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 persuasion rates of similar or larger magnitudes.
Surveys. Following Lazarsfeld, Berelson, and Gaudet [1944],
political scientists have widely used surveys to assess the impactof the media. A survey in this tradition [Kull, Ramsay, and Lewis
2003] finds that 33 percent of Fox News watchers believe (erroneously) that weapons of mass destruction were found in Iraq by
October 2003, compared to 22 percent for the overall sample. Thisimplies a persuasion rate f of 0.141 (Table IX). Gentzkow andShapiro [2004] examine the effect of media exposure in the Islamic world. The CNN audience was 30 percent more likely tobelieve, and the Al Jazeera audience was 40 percent less likely tobelieve that Arabs carried out the 9/11 attacks, compared torespondents who watched neither. The estimates imply persuasion 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

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1227

nonrational. In DellaVigna and Kaplan [2006], we present amodel of the last two explanations.
1. Endogeneity Bias. The findings may be spurious andinduced by entry of Fox News in towns that were independently becoming more conservative. Contrary to this interpretation, conditional on the controls, vote shares in1996 and voting trends in 1988 –1992 do not predict the
introduction of Fox News (Table III). Moreover, the introduction 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 introduction is unlikely to explain the results.
2. Rational Learning. To the extent that voters are initiallyuncertain about the bias of Fox News, exposure will havea (temporary) effect on beliefs and voting. Voters attributethe 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 theyear 2000 the conservative slant of Fox News should havebeen clear. Second, this explanation makes the predictionthat the media effect should disappear over time as votersbecome aware of Fox News’ political slant. Contrary tothis prediction, the Fox News effect over the 2000 –2004
period gets, if anything, larger (Table V).19
3. Nonrational Persuasion. A behavioral interpretation isthat viewers do not discount media bias strongly enough[Cain, Loewenstein, and Moore 2005] and therefore are subject to nonrational persuasion upon exposure. This interpretation can explain the persistence of the Fox News effect.
The two most plausible explanations, learning and persuasion, have very different long-run implications. Rational learning
predicts that Fox News’ impact is temporary. Nonrational persuasion predicts that Fox News permanently altered voting patterns 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 increasingaudience rates.

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QUARTERLY JOURNAL OF ECONOMICS

candidate-specific coverage, but rather to a general ideologicalshift. Beyond this, we cannot tell if the effect is due to conservative 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 inrecent years, the sudden introduction and expansion of the Fox
News cable channel from 1996 to 2000. We exploit the naturalexperiment 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, compared to the 1996 elections. A vote shift of this magnitude is likely
to have been decisive in the 2000 elections. We also find an effecton vote share in Senate elections, which Fox News did not cover,suggesting that the Fox News impact extends to general politicalbeliefs. Finally, we find evidence that Fox News increased turnout to the polls.
Based on this evidence and on microlevel audience data, weestimate that exposure to Fox News induced a substantial percentage of the non-Republican viewers to vote for the Republican
party, 3 to 8 percent according to the more inclusive audiencemeasure, 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 andvoting. We interpret the persuasion effect as a temporary learning effect for rational voters or a permanent effect for voterssubject to nonrational persuasion. These results suggest that themedia can have a sizeable political impact.
This paper leaves a number of open questions. First, while weanalyze the extensive margin of voting, we do not consider theeffect on the intensity of political convictions of Republican voters. 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

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1229

be interesting. Finally, we hope that more evidence on the effectof other sources of media bias, such as local papers and radio talkshows, will complement the evidence in this paper.
UC BERKELEY AND NBER
IIES, STOCKHOLM UNIVERSITYAPPENDIX 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 thePennsylvania State section is“KING OF PRUSSIA (Pa)—Comcast Cable. Counties: Delaware and Montgomery. Also serves: Collegeville, Graterford, Graterford Prison, Gulph Mills, [. . .] Upper Providence Twp. (Delaware County), Wayne. Account No:
PA0050. [. . .]Basic Service Subscribers 17,692. [. . .] Programming (received 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. Programming (via satellite): A&E; AMC; Bravo; CNBC; CNN; Comedy 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 indication of the county, which is listed separately (the number ofcounties is rarely more than three). In the example above, thecommunities listed belong to one of two counties (Delaware andMontgomery) in Pennsylvania. Since we do not know which belongs 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 cabledata 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

1230

QUARTERLY JOURNAL OF ECONOMICS

counties listed, but in this case we expect the county to be explicitly 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 communities, 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 cableofferings for the other towns. As a robustness check, we recompute 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 oflines listing cable channels in the Basic and Expanded Basic 1, 2,
and 3 Services. The estimated number of channels follows bymultiplying this number by 2.5, a conversion rate estimated on a
subsample of forty cable companies. Over this subsample, a regression of actual number of channels on forecasted number ofchannels yields an R 2 of 0.95 and a coefficient of 1.
Finally, it is worth noting that sometimes the number ofsubscribers 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, Arkansas, and Tennessee, the aggregation procedure generates avery 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, havea 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 thetown’s population is represented.

THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

1231

APPENDIX II: List of Controls for Tables III and IV

Census controls 2000
Population
High schoolSome college
College graduate
Male
African American
Hispanic
Employment
Unemployment
MarriedIncomeUrban
Census controls 2000–1990
Population
High schoolSome college
College graduate
Male
African American
Hispanic
Employment
Unemployment
MarriedIncomeUrban
Decile in potential subscribers
Decile 2
Decile 3
Decile 4
Decile 5
Decile 6
Decile 7
Decile 8
Decile 9
Decile 10
Decile in number of channels
Decile 2
Decile 3
Decile 4
Decile 5
Decile 6
Decile 7
Decile 8
Decile 9
Decile 10
U. S. House district fixed effects

Regression of Fox Newson determinants(Table III)

Regression of vote share
on Fox News
(Table IV)

Coefficient

Std. error

Coefficient

Std. error

(1)

(2)

(3)

(4)

⫺0.0004
0.0334⫺0.0218
0.06720.2285⫺0.013⫺0.1155
0.07590.3511⫺0.1057⫺0.0124⫺0.0293(0.0013)(0.2233)(0.1964)(0.1599)(0.2859)(0.1086)(0.1973)(0.1225)(0.3768)(0.1419)(0.0072)*(0.0251)⫺0.0003
0.0252⫺0.0664⫺0.0970.1146⫺0.0547⫺0.0571
0.03670.12120.0033⫺0.0012⫺0.0073(0.0001)***(0.0160)(0.0141)***(0.0103)***(0.0208)***(0.0061)***(0.0130)***(0.0089)***(0.0265)***(0.0078)(0.0004)***(0.0014)***⫺0.0189
0.0132⫺0.17160.0351⫺0.218⫺0.3921⫺0.0138⫺0.0367⫺0.3466⫺0.0786
0.0157⫺0.0039(0.0106)*(0.1997)(0.1931)(0.2097)(0.3099)(0.2173)*(0.3556)(0.1453)(0.2663)(0.1238)(0.0118)(0.0280)0.00180.0136
0.05960.0841⫺0.03110.0687⫺0.054⫺0.0209⫺0.0594⫺0.0105
0.00110.0029(0.0005)***(0.0136)(0.0154)***(0.0127)***(0.0238)(0.0181)***(0.0206)***(0.0109)*(0.0229)***(0.0111)(0.0010)(0.0018)⫺0.006
0.05340.04990.03880.05630.02590.022⫺0.00560.1786(0.0188)(0.0249)**(0.0295)*(0.0334)(0.0369)(0.0410)(0.0387)(0.0432)(0.0481)***⫺0.0007⫺0.0006⫺0.0022⫺0.0053⫺0.006⫺0.011⫺0.0105⫺0.0124⫺0.0127(0.0032)(0.0031)(0.0031)(0.0033)(0.0033)*(0.0034)***(0.0035)***(0.0035)***(0.0035)***0.03550.07780.051
0.03940.1122
0.33470.42920.41130.6475(0.0221)(0.0267)***(0.0287)*(0.0344)(0.0278)***(0.0464)***(0.0526)***(0.0541)***(0.0500)***0.00240.002⫺0.0005⫺0.00110.00010.0015⫺0.0017⫺0.0025⫺0.0014(0.0019)(0.0021)(0.0023)(0.0021)(0.0019)(0.0022)(0.0023)(0.0023)(0.0025)

X

X

X

X

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 thetotal population covered by a cable system.
*significant at 10 percent; ** significant at 5 percent; ***significant at 1 percent.

X
X
—
X
X

0.6796N ⫽ 9,256

X
X
X
—
X

0.5666N ⫽ 9,256

0.5574N ⫽ 9,802

X
X

X
X
X
—

0.0002(0.0015)(3)0.6765N ⫽ 9,802

X
X

X
X
—
X

0.0022(0.0014)

(4)

X
X
X
0.5371N ⫽ 9,131

X
X
X
0.6641N ⫽ 9,131

X
X—
X

0.0017(0.0014)⫺0.0003(0.0016)
X
X
X
—

(6)

(5)

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

0.004(0.0015)***0.0014(0.0016)

Availability of Fox News via cable in
2000
Control variables
Census controls: 1990 and 2000
Cable system controls
U. S. House district fixed effects
County fixed effects
Specifications
Unweighted
Include high-measurement-error obs.
Exclude HI, ND, NJ, WY
R2
N

(2)

(1)

Dep. var.

Presidential republication vote share change between 2000 and 1996

APPENDIX III: The Fox News Effect: Comparison with Earlier Results

1232
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THE FOX NEWS EFFECT: MEDIA BIAS AND VOTING

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