Open access success is not necessarily limited to open access journals. Subscription journals can also achieve considerable OA success - by allowing, or better yet, encouraging author self-archiving. Some subscription journals also work cooperatively with open access archives, ensuring both broader access to their journals and preservation.
Because open access policy of necessity specifies deposit in an open access archive, rather than publication in an open access journal, it is entirely possible for an alert subscription journal to exceed an open access journal in open access performance on this key criterion!
To calculate open access success when your journal's articles are open access through self-archiving:
Medical journals - the key archive is PubMed. Here are instructions for assessing compliance with the NIH Public Access Policy. The search described can be modified to calculate full OA compliance for your journal, i.e. simply search for articles in your journal, and see how many come up as full-text.
Not every journal has such a convenient subject archive for this search. In this case, I recommend selecting a sample of articles from your journal and conducting a search in the Bielefeld Academic Search Engine (BASE).
If your journal's open access performance is low, what can you do? One option is to provide information to your authors about their rights to self-archive, and encourage them to make use of these rights.
If your services are contracted out, and OA performance is low, it could be a great time to explore your options
If your journal has contracted with a publishing business, how helpful are they at encouraging authors to take advantage of self-archiving rights? This is especially important when authors are required by research funding agencies or their universities to make their work publicly or open accessible, as is becoming increasingly common. If service is lacking, this might be a good time to explore your options. If your journal made the decision to contract out some time ago, you might be pleased at the expanded range of options now available. This includes a growing number of fully open access publishers (OASPA is a good place to find these folk). There are many a great many university libraries that now provide journal hosting and support services; odds are that the members of your Editorial Board are associated with one or more of these university libraries.
This post is part of the Transitioning to Open Access series.