An interesting article in Publishing Trends . Discussing the New York Times ebook bestseller list, the article says:
The tracking system the paper developed was two years in the making. The Times is working on the lists with RoyaltyShare, and PT spoke to CEO Bob Kohn about the process.
Kohn said RoyaltyShare is helping the Times to validate the data it receives from e-book vendors by comparing the data against sales data those same vendors send to book publishers in the course of their regular reporting. “We have the cooperation and permission of the book publishers to do this, and the Times can trust that our validation is accurate, because we receive the publishers’ sales data directly from the e-book vendors and can assure the Times that the publishers cannot modify the data,” Kohn says.
The article goes on to discuss the USA Today list and various other markets. It isn’t all that easy to compile a list as publishers don’t share all the data:
Currently, though, says Philip Stone, Charts Editor at The Bookseller, “a couple of major players in the UK e-books market [still aren’t] willing to share their sales data with BookScan, or anyone else for that matter.” The Bookseller was only getting “a handful of download stats on a handful of books by a handful of publishers.” But after looking at the data available, they settled on a way to provide some information while working around tight-lipped vendors. The publication decided to begin publishing its own weekly e-book bestseller list that “without doubt is [currently] the best thing out there.”