Felix Oberholzer and Koleman Strumpf, of Harvard and the University of North Carolina, respectively, have published an interesting study on the effect of file sharing on record sales. They looked at album sales, actual download traffic for individual songs, and several other variables. Their main conclusion that file sharing had little or no effect on sales, and they could not reject the statistical hypothesis that filesharing had no effect at all on sales. Though these effects are not statistically significant, the data suggests that file sharing may boost the sale of the most popular albums, and may depress the sales of less popular albums, with a near-zero net effect on sales.
How much should we trust these results? I don’t know. The authors look like respectable academics, but their methodology is complex enough that I am not qualified to evaluate it. Perhaps a more qualified reader will have something to say about the study’s methodology.