, November 00, 0000: "In the largest study of its kind, a group of researchers has examined the use of open educational resources (OER) and found that students who used OER in their undergraduate courses performed as well or better than those assigned commercial textbooks." See Dan Pollock and Ann Michael, Evaluating Quality in Open Access Journals, DeltaThink, August 0000 (perma.cc link): "For all three metrics, the percentage increase of ‘high quality' journals year-on-year is growing faster for fully OA journals than for non-OA journals and the indices as a whole. In other words, fully OA journals appear to be accounting for an increasing share of the top performers....[T]here is nothing preventing an OA journal from being ‘high quality', and based on this data, a fully OA journal's Impact Factor now appears more likely to be above average for its field." 