The OA effect: new report

"This report presents the first major comparative analysis of usage data for OA and non-OA scholarly books, and provides an informed view of how a book benefits from OA publication. It also highlights the challenges involved in measuring the impact of OA on scholarly books and suggests that there is much to do across the whole scholarly communications network in supporting authors and their funders....

[From the report itself:]

Downloads: On average, there are just under 30,000 chapter downloads per OA book within the first year of publication, which is 7 times more than for the average non-OA book. • Citations: Citations are on average 50% higher for OA books than for non-OA books, over a four-year period. • Online mentions: OA books receive an average of 10 times more online mentions than non-OA books, over a three-year period...."