The open access movement began in the 1990s, as access to the World Wide Web became widely available and online publishing became the norm. The forerunners of open access were open source and open courseware.
There has been much discussion and analysis of whether open access affects the number of times a publication is cited. The following bibliography summarizes such studies, and provides links to the relevant publications:
Besides the effect of open access on citation impact, the economic and social impacts of open access have been analyzed:
Income Models for Supporting Open Access (from SPARC)
The Business Case for Open Access (from JISC)