Open Access briefing paper from SCONUL
Writing about web page http://www.sconul.ac.uk/news/OAbriefing/OA_impact_briefing.pdf
Alma Swan's latest briefing paper for the Research Libraries UK and SCONUL is available online. It has some great little graphs showing the citation advantage of open access publication for those in Engineering, Clinical Medicine and the Social Sciences. Also, a case study of the effect on citations of deposit in an institutional, open access repository, of an author's works.
The paper also explains the value of an open access repository in supporting the impact of research work, making the scientific findings and resources available to the public, helping to engage lay people in "citizen science" projects like Galaxy Zoo.
The briefing also discusses the value of OA to a knowledge-based economy, and it is a great, brief overview of all these topics.