Leading news outlets were 14 times more likely to identify the Heritage Foundation as conservative than they were to categorize the Brookings Institution as liberal, reports a new study in the Journal of Media Economics. The study, conducted by the Department of Justice economist Wayne Dunham, analyzed 25,000 news articles from six large daily newspapers and the Associated Press over the past couple of decades.

"The decision to attach an ideological label to a think tank when reporting a controversy," argues Dunham, "allows the reporter to frame one perspective as driven by an ideological/partisan agenda rather than the conclusion of a neutral or disinterested study." Six of the most cited think tanks were pigeonholed as conservative, including the American Enterprise Institute and the Hoover Institution. Another six were classified as liberal, including the RAND Corporation and the Urban Institute. The Cato Institute was more than twice as likely to be described as libertarian versus conservative.

Dunham finds that mainstream news outlets "associate ideological frames with conservative (or libertarian) think tanks three to six times as often as they do with liberal think tanks." Attaching ideological labels to analyses done by conservative think tanks implies that they are less objective than those done by their liberal counterparts.