Do free book releases (gratis and/or libre) affect books sales in a pos­i­tive or neg­a­tive way? To try and find out, John Hilton of Brigham Young Uni­ver­sity tracked the sales of books 8 weeks prior and fol­low­ing a num­ber of pro­mo­tional free release from var­i­ous publishers.

On March 4 of this year, Ran­dom House announced that it would release five books for free through its sci­ence fic­tion por­tal, all of which came in down­load­able PDF files (among other for­mats). Hilton recorded the before and after book sales and found that “one of the five books has had zero sales in 2009. So no sales before or after the free ver­sion. But the other four books all saw sig­nif­i­cant sales increases after the free ver­sions were released. In total, com­bined sales of the five books were up 11%. Together they sold 4,633 copies the 8 weeks prior to being released free and 5,155 copies the eight weeks after being released.”

How­ever the results were quite con­flict­ing, with some see­ing an upturn in sales (as above) and oth­ers hav­ing a dras­tic drop. The debate continues.