How Do Free Online Book Releases Affect Sales?

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.