Study riddled with flaws
In "
A Measure of Media Bias" (pdf), Groseclose and Milyo attempted to "measure media bias by estimating ideological scores for several major media outlets" based on the frequency with which various think tanks and advocacy organizations were cited approvingly by the media and by members of Congress over a 10-year period. In order to assess media "bias," Groseclose and Milyo assembled the ideological scores given to members of Congress by the liberal group Americans for Democratic Action; examined the floor speeches of selected members to catalog which think tanks and policy organizations were cited by those members; used those citations as the basis for an ideological score assigned to each think tank (organizations cited by liberal members were scored as more liberal, whereas organizations cited by conservative members were scored as more conservative); then performed a content analysis of newspapers and TV programs to catalog which think tanks and policy organizations were quoted. If a news organization quoted a think tank mentioned by conservative members of Congress, then it was said to have a conservative "bias." As Groseclose and Milyo put it:
As a simplified example, imagine that there were only two think tanks, and suppose that the New York Times cited the first think tank twice as often as the second. Our method asks: What is the estimated ADA score of a member of Congress who exhibits the same frequency (2:1) in his or her speeches? This is the score that our method would assign the New York Times.
In other words, the study rests on a presumption that can only be described as bizarre: If a member of Congress cites a think tank approvingly, and if that think tank is also cited by a news organization, then the news organization has a "bias" making it an ideological mirror of the member of Congress who cited the think tank. This, as Groseclose and Milyo define it, is what constitutes "media bias."
When Carlson asked him to explain the study, Milyo misrepresented his own study. Milyo noted that the study did not look at editorials, then said, "Of course, but that's how bias sneaks into news coverage. The reporter doesn't say, 'I think this.' He says, 'According to our expert, say, Barbra Streisand, this is true.' Right? It's the choice of the experts that allows the opinion to get in." But Milyo's example of Streisand -- as though a news organization would actually cite her as an "expert" -- is flawed, considering that the study examined only mentions of think tanks and advocacy organizations (not of individual experts). Milyo ended his interview by telling Carlson, "My wife's a big fan [of Carlson]."