The introduction of Fox News had a small but statistically significant effect on the vote share in Presidential elections between 1996 and 2000.
Does media bias affect voting? Over 70 percent of Americans believe that there is either a great deal or a fair amount of media bias in news coverage. Evidence of bias ranges from the topic choices of the New York Times to the choice of think tanks to which the media refer in their broadcasts.
In The Fox News Effect: Media Bias and Voting (NBER Working Paper No. 12169), authors Stefano DellaVigna and Ethan Kaplan address this question by looking at the entry of Fox News into cable markets and its subsequent impact on voting. Between October 1996 and November 2000, the conservative Fox News Channel was introduced into the cable programming of 20 percent of American towns. Using voting data for 9,256 towns, the authors investigate whether Republicans gained vote share in towns where Fox News entered the cable market by the year 2000.
They find that the introduction of Fox News had a small but statistically significant effect on the vote share in Presidential elections between 1996 and 2000. Republicans gained an estimate of between 0.4 and 0.7 percentage points in the towns that broadcast Fox News. They also find that Fox News had a significant effect on Senate vote share and on voter turnout. Their estimates imply that Fox News convinced 3 to 8 percent of its viewers to vote Republican according to a first audience measure, and 11 to 28 percent according to a second, more restrictive audience measure.
The authors also analyzed whether Fox News affected voting in those races where it did not cover the candidates directly, as was the case in most Senate races. In that way, they are able to estimate whether the influence of Fox News is candidate-specific or whether it extends to general political beliefs. The researchers find that Fox News significantly increased the Republican vote share for Senate, by 0.8 percentage points. Additionally, the effect was not larger for the one Senatorial race that Fox News did cover heavily, the New York state race between Hillary Clinton and Rick Lazio. Fox News appears to have induced a generalized ideological shift.
Rupert Murdoch introduced the 24-hour Fox News Channel in October 1996 to compete with CNN. Like CNN, it was offered only via cable and, to a smaller extent, via satellite. Thanks to an aggressive marketing campaign, a number of cable companies added Fox News to their programming over the next four years. That geographical expansion was accompanied by a corresponding increase in the audience share. By June 2000, 17.3 percent of the U.S. population reported watching Fox News regularly.
The nature of the cable industry induces substantial geographical variation in access to Fox News. Cable markets are natural monopolies with capacity constraints on the number of channels they offer. The availability of Fox News in a town depends on whether the local cable company decides to add it to the programming, possibly at the expense of another channel. Cable companies in neighboring towns often make different decisions, creating idiosyncratic variation in access. This allows the authors to compare voting patterns in neighboring towns that are similar except for the availability of Fox News. Their dataset covered 28 states.
Since Fox News was available in about 35 percent of households in 2000, its impact on the national two-party vote share that year is estimated to be 0.15 to 0.2 percentage points, or 200,000 votes nation-wide. While this vote shift is small compared to the actual 3.5 percentage point shift in the authors' sample between 1996 and 2000, it is still likely to have been decisive in the close 2000 presidential elections.
The authors also point out that their results have implications for policy, such as for the regulation of media concentration. If media bias alters voting behavior, then deregulation of media markets may have a large impact on political outcomes
-- Les Picker