Stop the presses: News coverage in the editorially conservative Wall Street Journal tilts to the left more than that of any other major news outlet. So says a study released earlier this year and co-authored by UCLA Political Science Professor Timothy Groseclose and University of Missouri economist Jeffrey Milyo. The professors believe it is the first objective analysis of ideological bias in the mainstream media.

Titled “A Measure of Media Bias,” the study found that bias in news coverage hewed pretty closely to general assumptions — in general, the media tilts left. The methodology used in the study, however, is anything but mainstream. The researchers determined the political slant of news coverage using the same system that ranks the ideological purity, or lack of it, among members of Congress.

“If the media are largely liberal,” says Groseclose, an expert on congressional politics, “we asked ourselves, which U.S. senators and representatives do they most sound like?”

To answer the question, he and Milyo turned to data from Americans for Democratic Action (ADA), a self-described liberal lobbying group that maintains a record of how many times each lawmaker has voted on the liberal or conservative side of an issue, and assigns scores on a 0100 scale for each lawmaker, with 100 being the most liberal.

The authors also analyzed speeches given by U.S. lawmakers, noting the number of times they referred to think tanks and policy groups, and examined some 20,000 media articles over a 10-year period. Whenever a media outlet had a citation pattern similar to that of a lawmaker, both were assigned comparable ADA scores.

The results: With an ADA of 73.7, the New York Times and CBS Evening News jointly ranked as the second-most liberal outlets after the Journal, which scored 85.1. The Journal’s parent company, Dow Jones and Co., dismissed the research as “logically suspect and simply baffling in some of its details.”

And that’s on the record.