Barrier-free access helps readers find and retrieve the research they need, and helps authors reach readers who can apply, cite and build on their work. Knowledge has always been a “public good” in the theoretical sense that consumption doesn’t deplete it (it’s “nonrivalrous”) and consumption is available to all (it’s “nonexcludable”). OA makes knowledge a public good in practice.
OA is made possible by copyright-holder consent and the internet. We don’t expect copyright-holder consent from musicians, novelists, movie-makers, or other creators who hope to make a living by selling their work. (Despite this, we do get consent from some of them.) The real opportunity for OA is among scholars who write journal articles for impact, not for money.
There are many ways to deliver OA, but two vehicles dominate. OA can be delivered by peer-reviewed journals (in the jargon, “gold” OA) or by repositories (“green” OA).
OA journals can use any of a dozen different business models for paying their bills. (OA does not presuppose that publishing is costless.) OA publishers can be for-profit or non-profit. Some use traditional methods of peer review, in order to tweak just the access variable of scholarly journals. But others use new and innovative models of peer review taking advantage of the digital network for gathering and disseminating peer judgments. More than 8,000 peer-reviewed OA journals are now listed in the Directory of Open Access Journals.