Open Access benefits researchers, institutions, nations and society as a whole. For researchers, it brings increased visibility, usage and impact for their work. Institutions enjoy the same benefits in aggregated form. There is growing evidence to show that countries also benefit because Open Access increases the impact of the research in which they invest public money (see Houghton and Sheehan's study on the economic impact of enhanced access to research findings) and therefore there is a better return on investment. Society as a whole benefits because research is more efficient and more effective, delivering better and faster outcomes for us all.
Open Access is the alternative to Closed Access (or Subscription Access or Toll Access). Traditionally, journals have been sold on subscription to libraries. In the age of print-on-paper this was the only model available that enabled publishers to disseminate journals and recoup the cost. Unfortunately, this meant that only researchers in institutions that could afford to pay the subscription charges were able to read journal articles. Even wealthy universities could only afford a proportion of the world's research literature. For institutions in poorer countries this proportion is tiny or even non-existent. At the beginning of this millennium, more than half the research-based institutions in the poorest countries had no current journal subscriptions and over 20% had an average of two subscriptions.
Now, in the age of the World Wide Web, it is possible for research findings to be disseminated free of charge to anyone who wishes to read them. Those with access to the journals in their libraries will access the articles as before - though some people say that it is actually quicker and easier to access Open Access copies through a search engine (one or two clicks) than to access the published article in a journal through their library website (which normally takes several steps). Those who do not have the journals they want in their library can use Google or other Web search engines to track down the Open Access literature in institutional and subject repositories.
Repositories can provide usage data to show the number of times articles have been downloaded. The levels of this type of usage can be surprising. For example, in New Zealand, the University of Otago’s Business School set up an Open Access repository in November 2005: by February 2006, with just 220 articles in it at the time, it had received almost 20,000 ‘hits’ (downloads) (Stanger and McGregor, 2006). No doubt many of these are translating into citations over time.
Developing country repositories also enjoy a high level of usage of repositories, which are at last providing to the rest of the world the outputs from scholars in those countries who previously had difficulty publishing in 'western' journals. For example, the Institutional Repository of the Universidad de Los Andes in Venezuela, with ~14,000 records, registered 502,000 full text downloads in 2008 from both regional and international users.