C. Edward Watson was interviewed in a Teaching in Higher Ed podcast about his research when he was at the University of Georgia where he conducted a study about OER and equity.
Quote around the 19-20 minute mark:
“We found that course grades improved at greater rates for nonwhite students and Pell eligible students. In other words, those that we thought that a free textbook would help. Those folks really saw a difference. We also saw significant decreases in DFW rates, a greater rates for nonwhite and Pell eligible students. In fact, looking just at those subgroups, we saw DFW rates drop by a third. So, it really is sort of the notion that that OERs are doing more to make the classroom more equitable, more fair. “