An analysis of article downloads from 2,812 academic and professional journals published by 13 presses in the sciences, social sciences, and humanities reveals extensive usage of articles years after publication.
Measuring usage half-life–the median age of articles downloaded from a publisher’s website–just 3% of journals had half-lives shorter than 12 months. Nearly 17% of all journals had usage half-lives exceeding six years.
While journal usage half-lives were typically shorter for journals in the Health Sciences (median half-life: 25-36 months), they were considerably longer for journals in the Humanities, Physics and Mathematics (median half-life: 49-60 months). Overall, the median half-live for all journals was three to four years.
The study involves a variety of non-profit society, association, university and commercial publishers operating under a diversity of business and access models. Analyzed by ten major subject classifications, the study illustrates substantial variation in the usage half-lives of journals both within and across subject disciplines.
As the author of the study, it is my hope that evidence-based studies such as this will help to inform those developing public policy and may aid in setting access embargoes.