Center for Media and Public Affairs at George Mason University:
A leading media fact-checking organization rates Republicans as less trustworthy than Democrats, according to a new study by the Center for Media and Public Affairs (CMPA) at George Mason University. The study finds that PolitiFact.com has rated Republican claims as false three times as often as Democratic claims during President Obama’s second term. Republicans continue to get worse marks in recent weeks, despite controversies over Obama administration statements on Benghazi, the IRS and the AP.
Of course, such a study assumes that organizations such as Politifact fairly choose statements to analyze, and analyze those statements fairly. Both of these points are contested by some Republicans, as I canvass in my recent article, A Constitutional Right to Lie in Campaigns and Elections?
UPDATE: John Sides makes similar points.