Registered users have free access to research articles that are six months old or older. However, the tables of contents of each issue (such as the issues for 2007) of the NEJM indicate that the free full text is available immediately, without registration, for a minority of the contents of each issue.
I’ve looked at the 15 most recent issues (the issues from September 6, 2007 to December 13, 2007) and have tabulated the contents for which the free full text is already available. The section that lists the “Article Summaries” was omitted, as were the “Book Reviews”. A total of 315 individual items were identified in the contents of these 15 issues. The free full text was accessible upon publication for 103 of these items (33%). The largest number of items (92) in an individual section was in the “Correspondence” sections of these issues. The free full text was immediately accessible for 26 of these letters (28%).
The “Perspectives” section of the NEJM “Provides a quick assessment of a single, important topic“. There were 36 items in the “Perspective” sections of these 15 issues, of which 25 (69%) were immediately freely accessible. Prompt free access was also provided to 20 of 29 (69%) of items in the “Images in Clinical Medicine” sections.
Of a total of 60 “Original Articles” in these 15 issues, only 8 (13%) were freely accessible upon publication, and of a total of 35 “Editorials”, 7 were already freely accessible (20%).
Why are some items in the table of contents freely accessible immediately upon publication, while others are not? I’ve been unable to find an answer to this question in the FAQs that are available via the NEJM site. I’ve contacted the journal via email in an attempt to obtain an answer.
Added December 26, 2007:
A message, NEJM – Change in Access Policy for Research Articles, was posted to the Liblicense-L mailing list by Tom Richardson, Director, Institution Sales & Service for NEJM, on December 22, 2007. Excerpts:
As of December 19, 2007, the Journal now provides free access to original research articles (Original Articles and Special Articles), six-months after publication, with no registration required.
The Journal will continue to make articles of immediate public health importance available free to all visitors upon publication.
A copy of this message was posted by Peter Suber to the SPARC Open Access Forum on December 23, 2007: NEJM – Change in Access Policy for Research Articles.