More hard data on the impact of free/pirated downloads on book-sales

Brian F. O’Leary has posted slides updating his quantitative research on the effect of “piracy” and/or free giveaways on book-sales, done independently using data from O’Reilly and Random House (the largest tech publisher and general publisher in the world, respectively). The new slides, from the recent Book Expo America, expand the work with a larger data-set, and confirm the earlier findings that free downloads are broadly correlated with higher overall sales (though correlation is not causality!).