This was a posted on liblicense-l:
"Is it cheaper in an Open Access producer-pays model to take an
institutional membership over paying per article published? The results
of this analysis of two research institutions suggests that institutions
could save money if they paid by the article."

Philip Davis (Cornell) and David Stern (Yale) conducted a study to determine whether it was cheaper in an Open Access producer-pays model for a library to have an institutional membership over paying per article published.

The study was done at Cornell and Yale and it turns out that it can be actually cheaper for the libraries to pay per published article and not have an institutional membership. This is interesting since Cornell and Yale are highly respected and highly published research institutions, one would think that the and institutional membership would have been the most cost effective method.

This is a very interesting study. Here is their manuscript and their spreadsheet analysis. I look forward to reading more about this.