Barton Beebe, Associate Professor of Law at the Benjamin N. Cardozo School of Law of Yeshiva University, has released "An Empirical Study of U.S. Copyright Fair Use Opinions, 1978-2005."
Here's an excerpt from the e-print's abstract:
This Article presents the results of the first empirical study of our fair use case law to show that much of our conventional wisdom about that case law is wrong. Working from a data set consisting of all reported federal opinions that made substantial use of the Section 107 four-factor test for fair use through 2005, the Article shows which factors and subfactors actually drive the outcome of the fair use test in practice, how the fair use factors interact, how courts inflect certain individual factors, and the extent to which judges stampede the factor outcomes to conform to the overall test outcome. It also presents empirical evidence of the extent to which lower courts either deliberately ignored or were ignorant of the doctrine of the leading cases, particularly those from the Supreme Court.
Source: Beebe, Barton. "An Empirical Study of U.S. Copyright Fair Use Opinions, 1978-2005." SSRN (2007).