The Fox News effect: More Republicans

The economists Stefano DellaVigna (UC Berkeley) and Ethan Kaplan (Stockholm University) have published the final version of their paper "The Fox News Effect: Media Bias and Voting" in the Quarterly Journal of Economics (sub. req. - see also an earlier non-gated version). Here is the abstract, which summarizes a striking result that has apparently held up under scrutiny:

Does media bias affect voting? We analyze the entry of Fox News in cable markets and its impact on voting. Between October 1996 and November 2000, the conservative Fox News Channel was introduced in the cable programming of 20 percent of U. S. towns. Fox News availability in 2000 appears to be largely idiosyncratic, conditional on a set of controls. Using a data set of voting data for 9,256 towns, we investigate if Republicans gained vote share in towns where Fox News entered the cable market by the year 2000. We find a significant effect of the introduction of Fox News on the vote share in Presidential elections between 1996 and 2000. Republicans gained 0.4 to 0.7 percentage points in the towns that broadcast Fox News. Fox News also affected voter turnout and the Republican vote share in the Senate. Our estimates imply that Fox News convinced 3 to 28 percent of its viewers to vote Republican, depending on the audience measure. The Fox News effect could be a temporary learning effect for rational voters, or a permanent effect for nonrational voters subject to persuasion.

DellaVigna and Kaplan have also posted a forthcoming edited volume chapter titled "The Political Impact of Media Bias" that explores their results in more detail. Here is part of the introduction:

We use our estimates of the impact of Fox News to compute persuasion rates, that is, the share of Democratic voters that switched to voting Republican because of exposure to Fox News. We also compute mobilization rates, that is, the share of non-voters that turn out to the polls because of exposure to Fox News. This section expands substantially on the discussion of persuasion rates in DellaVigna and Kaplan (2007). In our baseline calibration, we estimate that 4 to 8 percent of the audience was persuaded to vote Republican because of exposure to Fox News. When we allow for a separate effect on non-voters, we find that the mobilization effect of Fox News may have accounted for one sixth to one hundred percent of the impact. We obtain similar persuasion rates for the effect of Fox News on US Senate elections. These estimates imply a sizeable, and large in some specifications, impact of the media on political decisions.

Note to the haters: If this result seems obvious, remember (as I've pointed out before) that it is difficult to show cause and effect when studying the media because the outlets' audiences are self-selected. Thus, showing that Fox viewers are mostly conservative would tell us nothing about whether watching the channel made them more conservative. In this case, DellaVigna and Kaplan are exploiting the idiosyncratic rollout of the channel across the country to estimate an exogenous effect on aggregate turnout and voting.

Comments

[Rob]

"Persuasion" rate seems like a loaded term. Is that what news media do--persuade voters how to vote? If that term were used to describe the consequence of obtaining news from CNN, MSNBC, the major networks, wouldn't you find that objectionable?

Perhaps a more benign interpretation of these data is that the marketplace of ideas is alive and well. When the marketplace of ideas was enhanced by the addition of Fox News, voters responded. That suggests that perhaps the marketplace of ideas they'd been offered prior to the introduction of Fox News was deficient.

[Howard]

Rob -

By "the marketplace of ideas" do you mean "the marketplace of opinions”?

Presenting a constant and consistent (as in unchanging) set of opinions is acting to persuade.

Additionally, the act of being persuaded is not a beneficial thing in itself. It doesn't prove that any "enhancement" has occurred.

A real enhancement occurs when ideas are introduced and debated (in conjunction with the actual facts) and people are able to make informed decisions on their own.