MEASURING THE FOX NEWS EFFECT

I was reading a short description of new research on opinion formation and in addition to finding a new concept - "bounded confidence" - I also was led to this 2006 NBER paper:

The Fox News Effect: Media Bias and Voting
Stefano DellaVigna, Ethan Kaplan

NBER Working Paper No. 12169
Issued in April 2006
NBER Program(s): POL

Does media bias affect voting? We address this question by looking at 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 US towns. Fox News availability in 2000 appears to be largely idiosyncratic. 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 gain 0.4 to 0.7 percentage points in the towns which broadcast Fox News. The results are robust to town-level controls, district and county fixed effects, and alternative specifications. We also find a significant effect of Fox News on Senate vote share and on voter turnout. Our estimates imply that Fox News convinced 3 to 8 percent of its viewers to vote Republican. We interpret the results in light of a simple model of voter learning about media bias and about politician quality. The Fox News effect could be a temporary learning effect for rational voters, or a permanent effect for voters subject to non-rational persuasion.