While it is undeniably simple and less subjective than some methods might be, there is a crucial factor that shokwave's experiment overlooks: The relative ease of poking fun at the two sides. For instance, if George W. Bush gets parodied more than Bill Clinton did, is that necessarily because the newspaper or cartoonist is liberal? Or could it just as easily be simply because he is exceptionally ripe for satire? You may find that the difference in satirisability between 'liberal' and 'conservative' targets is substantial and pervasive, creating a systematic error in the data from this experiment which should not be ignored...