Open Access is a process that makes journal articles freely available via the Internet to the general public. Washington State University describes open access as pushing back against "the traditional model of publishing whereby authors sign their scholarly work over to publishers, who in turn charge academic institutions and the general public large sums of money for access to this information. In general, the open access movement supports the idea that research--particularly research funded by the public--should be available to the public at no charge." (Washington State University)
There are three types of Open Access (Gold OA, Green OA, Hybrid OA).
The NIH Public Access Policy ensures the public has access to the published results of NIH-funded research, and requires scientists to submit the final peer-reviewed journal manuscripts that arise from NIH funds to PubMed Central (PMC) upon acceptance for publication. The policy requires that these papers become accessible via PMC no later than 12 months after publication.
Plan S, a controversial initiative developed by European journal publishers, will make any works “generated through research grants” from specific countries, available open access without embargo dates. It is scheduled to take effect in 2020. Because a significant percent of American researchers collaborate with colleagues outside the U.S., any works arising from their research will have to be published in Plan S-compliant journals. An ever-growing number of national funding agencies and charitable organizations worldwide are committed to funding and supporting the principles of Plan S. (https://www.coalition-s.org/)
Open Access Policies & Publishing contains good background information from the ACRL Scholarly Communication Toolkit.
Predatory publishers exploit the Open Access publishing model. Unfortunately, neither the minimal standards Open Access journals must meet, nor the quality of peer review, were ever delineated. A Statement on Article Publication Resulting from NIH Funded Research was issued in November 2017 and a post on NIH's Extramural Nexus site, Continuing Steps to Ensuring Credibility of NIH Research: Selecting Journals with Credible Practices, contains comments about that statement.
For more information, please see our Predatory Journals page.