Sarah Beaubien, Julie Garrison, and Doug Way have published "Evaluating an Open Access Publishing Fund at a Comprehensive University" in the Journal of Librarianship and Scholarly Communication.
Here's an excerpt:
Wanting to learn how faculty have benefitted from an open access publishing fund, Grand Valley State University Libraries surveyed recipients of the fund. The survey asked authors why they chose an open access publishing option and whether the fund influenced this decision. Authors were also asked whether they perceived that selecting an open access option broadened exposure to their work and about their likelihood of choosing open access in the future.