SUMMARY: (See also Letters, July 17.) Evans & Reimer (E & R) (Open Access and Global Participation in Science Science 20 February 2009) show that there is an 8-20% increase in citations for articles that provide delayed (embargoed) open access (OA) (free online access). This OA citation advantage would undoubtedly be even greater if the OA were provided immediately upon publication, rather than a year or more thereafter. E & R also examine only publisher-provided OA journals (“Gold OA”), and not at author-provided OA to their own self-archived journal articles (“Green OA”). That too would raise the OA advantage. E & R also found that a large component of the extra citation impact for their sample came from the “have-nots” in the Developing World — the researchers whose institutions could not afford subscription access. But the Developed World has plenty of have-not institutions too; and even Harvard cannot afford to subscribe to all journals in which there are articles Harvard researchers need. So it is virtually certain that a careful analysis in terms of institutional subscription budget size would reveal that the citation advantage comes also from the have-nots in the Developed World too.
Three critiques of E & R:
Evans & Reimer (2009) (E & R) show that a large portion of the increased citations generated by making articles freely accessible online (“Open Access,” OA) comes from Developing-World authors citing OA articles more. It is very likely that a within-US comparison based on the same data would show much the same effect: making articles OA should increase citations from authors at the Have-Not universities (with the smaller journal subscription budgets) more than from Harvard authors. Articles by Developing World (and US Have-Not) authors should also be cited more if they are made OA, but the main beneficiaries of OA will be the best articles, wherever they are published. This raises the question of how many citations – and how much corresponding research uptake, usage, progress and impact – are lost when articles are embargoed for 6-12 months or longer by their publishers against being made OA by their authors.
It is important to note that E & R’s results are not based on immediate OA but on free access after an embargo of up to a year or more. Theirs is not an estimate of the increase in citation impact that results from immediate Open Access; it is just the increase that results from ending Embargoed Access. In a fast-moving field of science, an access lag of a year can lose a lot of research impact, permanently.