Responding to criticism of how it pays authors enrolled in its Kindle Unlimited e-book subscription service and Kindle Owners Lending Library, Amazon is changing its royalty terms. Beginning July 1, authors enrolled in either program will be paid based on the number of pages read in each of their books that are borrowed. Additionally, Amazon plans to add $7.8 million to the May KDP Select global fund, the royalty pool from which KDP Select authors are paid.

Since the launch of the programs, which are predominantly filled with KDP titles, many authors have complained that their earnings have dropped. KDP authors were originally paid based simply on the number of times their book was borrowed. Now authors will be paid based on how many pages in their borrowed title have been read.

In a statement that acknowledged it has received extensive feedback on how to improve its payment system, Amazon said the one constant been the complaint that payments were made based solely on borrows. Amazon said that many authors claimed "paying the same for all books regardless of length may not provide a strong enough alignment between the interests of authors and readers." It then added: "We agree.”

Amazon also released payment statistics for the first half of 2015. KDP Select authors, Amazon said, are on track to earn over $60 million in the first half of 2015 from books read in KU and KOLL. In addition, total royalties across subscription and a la carte sales earned by KDP Select authors in the U.S. are on track to more than double in the first half of 2015, compared to the same period last year. And, Amazon added, its authors have continued to renew their titles in KDP Select at rates in excess of 95% each month, since Kindle Unlimited launched.

“We think this is a solid step forward and better aligns the interests of readers and authors," Amazon's statement continued. "Our goal, as always, is to build a service that rewards authors for their valuable work, attracts more readers and encourages them to read more and more often.”