Partisans often complain of the partisan bias in media coverage, which these critics say systematically disadvantages whatever political viewpoint they prefer. Conservatives decry "National Liberal Radio" or, more plausibly, the leftward slant of MSNBC, whereas liberals mock the "fair and balanced" moniker of FoxNews.

The first year of the Tea Party movement provides yet another litmus test of these charges. This movement represents a new and vocally conservative actor that might tempt different media outlets to cover it in ways that reflect underlying biases.

To test for such prejudice, the University of Washington undergraduate students in my Political Deliberation course created a series of content analytic categories that they applied to a representative sampling of 55 news articles from April 2009 to April 2010 collected by UW graduate student Wenlin Liu. Extracted from the websites of FoxNews, NPR, and CNN, this sample is small, but some of its findings are striking.

At the very least, a careful look at these articles suggests interesting differences—and surprising similarities—in how these outlets have covered the Tea Party.

One might expect that different networks would vary in whether they see the Tea Party as helping or hurting the two major political parties. Students calculated the number of lines in each article that suggested how the Tea Party was affecting each party, and from this, I calculated a simple index from minus 10 to plus 10 to measure the Tea Party's impact.

On balance, CNNs reporting suggested that the Tea Party would hurt the GOP a little (-5) but have no effect on the Democrats. NPR suggested it could hurt both parties (-6 for GOP, -4 for Dems), and FoxNews' reporting suggested it would be a net benefit for the GOP (+5) and devastating for the Dems (-10).

Next, consider how the media report on the general public's sentiments toward the Tea Party. To date, every poll conducted has shown divided public opinion, with many Americans supporting the Tea Party and many others opposing it. Nonetheless, every one of the media outlets was more likely to include text indicating public support for the Tea Party than text indicating public opposition. NPR and Fox had roughly equal numbers, with three-quarters of their articles mentioning public support compared to only two-thirds noting opposition, whereas CNN devoted relatively few lines to either sentiment.

A particular feature my students chose to investigate was how the first and last source cited in each story portrayed the Tea Party. These citations have special importance because they capitalize on either the primacy effect (the strong impression from the first thing you hear) or the recency effect (you remember the last thing that you hear). The pattern was roughly consistent across all three sources: 56 percent of the first sources had something nice to say, only 18 percent were critical, and the remainder were neutral. As for getting in the last word, 49 percent of the last sources cited ended on a positive note, and 35 percent closed on a negative one.

Looking at the types of sources used by these different media outlets reveals the most striking differences among the networks. The articles at CNN.com distinguish themselves for their thin sourcing. CNN used the fewest sources overall, with a relatively even sprinkling across the spectrum (favoring Republicans, academics, and pundits). The articles at FoxNews had the largest number of political and official sources, giving the most ink to Tea Party organizers/officers and almost no quotes to the lay public.

NPR stood out compared to CNN and Fox as the most likely to include in its stories the voices of ordinary citizens, along with Tea Party participants and organizers. NPR also showed the clearest imbalance in sourcing. These articles quoted seven Republicans for every Democrat, and a quarter of the articles included Tea Party organizers compared to almost none featuring anti-Tea Party citizen demonstrators or activists.

Once again, these findings come from the small sample of Tea Party articles produced by CNN, NPR, and FoxNews thus far. Moreover, the codings were an undergraduate project, not a formal academic study. In spite of those limitations, these data make clear that the Tea Party organizers needn't rely exclusively on FoxNews to get out its message. In the Tea Party’s first year, the media represented in our sample offered more than a fair shake and presented a relatively muted opposition. As the November 2010 election approaches, that pattern of coverage may change, but one can expect that the favorable early reporting benefitted the movement and helped make it the force it has become today.