University policies may be voluntary (i.e. they request that researchers make their work Open Access) or mandatory (i.e. they require that researchers make their work Open Access. The evidence shows that only mandatory policies produce the level of self-archiving from researchers that fill repositories.
Basic issues involved in wording an Open Access policy
Types of institutional Open Access policy wording
An optimal institutional Open Access policy
The University of Liege Open Access policy wording
The Immediate-Deposit/Optional-Access (ID/OA) mandate: rationale and model
Optimizing OA self-archiving mandates: What? Where? When? Why? How?
How to integrate university and funder Open Access mandates
Which green OA mandate is optimal?
Open Access policy options for funding agencies and universities
Three principles for university Open Access policies
Three principles for university Open Access policies (PDF version)
University of Stirling's policy
Queensland University of Technology's policies (research outputs and theses)