The Short-Term Influence of Free Digital Versions of Books on Print Sales

Increasingly, authors and publishers are freely distributing their books electronically to increase the visibility of their work. A vital question for those with a commercial stake in selling books is, “What happens to book sales if digital versions are given away?” We used BookScan sales data for four categories of books (a total of 41 books) for which we could identify the date when the free digital versions of the books were made available to determine whether the free version affected print sales. We analyzed the data on book sales for the eight weeks before and after the free versions were available. Three of the four categories of books had increased sales after the free books were distributed. We discuss the implications and limitations of these results. The Short-Term Influence of Free Digital Versions of Books on Print Sales Introduction A growing number of authors and publishers freely distribute their books electronically to increase the visibility of their work. These books, for both academic and general audiences, cover a wide variety of genres, including technology, law, fantasy, and science fiction. Some authors claim that free digital distribution has increased the impact of their work and their reputations as authors. [1] But beyond increased exposure, a vital question for those with a commercial stake in selling books is, “What happens to book sales if digital versions are given away?” One answer may come from the National Academies Press (NAP), which makes the text of all of its publications freely accessible. “Consequently,” reported Michael Jensen, Director of Publishing Technologies at NAP, “we are very well indexed by search engines.” [2] Jensen wrote that as a result of this indexing they receive many visitors, a small percentage of whom purchase books. Jensen reported that NAP’s 1997 publication “Toxicologic Assessment of the Army’s Zinc Cadmium Sulfide Dispersion Tests” had 11,500 online visitors in 2006. Those visitors “browsed approximately four book pages each. Of those, four bought a print book at $45, and two bought the PDF at $37.50. So 0.05% of the visitors to that particular book purchased it, even though they could read every page free online.” [3] Thus, a nine-year-old out-of-print publication that otherwise would likely have been inaccessible was viewed 11,000 times and purchased six times. The Oriental Institute at the University of Chicago digitally distributes free copies of its books, and recently reported that print sales have not decreased. Specifically they noted that “[a]fter the complimentary distribution of twenty-one titles in 2008 that had for many years only been available in print, sales of these titles increased by 7% compared with the previous two years.” [4] The question of how freely distributing an electronic version of a work affects print sales is difficult, if not impossible, to answer experimentally because there is no way to simultaneously release and not release free versions of a book. It is not possible to determine causation; nevertheless, the effect of free distribution on print sales is an important issue to examine. In the present study we explored how free digital book distribution influenced book sales in the short term by examining a series of books that were released in print at one point in time, and then later released in a free digital format. Our specific question was, “Are book sales in the eight weeks following a book’s free digital release different from the eight weeks prior to this release?” Because most books have a pattern of declining sales as time goes by, our assumption was that sales would decrease slightly in the eight weeks following the free release.