No abstract

It has been shown (S. Lawrence, 2001, Nature, 411, 521) that journal articles which have been posted without charge on the internet are more heavily cited than those which have not been. Using data from the NASA Astrophysics Data System (ads.harvard.edu) and from the ArXiv e-print archive at Cornell University (arXiv.org) we examine the causes of this effect.Recently Lawrence (2001) and Brody, et al. (2004) have demonstrated that articles which are available on-line at no charge are cited at substantially higher rates than those which are not. Kurtz (2004) has shown that restrictive access policies can cut article downloads to half the free access rate.There are (at least) three possible, and non-exclusive, explanations for the effect noted by Lawrence (2001) and Brody, et al. (2004).

In this report we examine the change in citation behavior since the introduction of the arXiv e-print repository (Ginsparg, 2001). It has been observed that papers that initially appear as arXiv e-prints get cited more than papers that do not (

Are the e‐prints (electronic preprints) from the arXiv repository being used instead of journal articles? We show that the e‐prints have not undermined the usage of journal papers from the four core journals in astrophysics. As soon as the journal article is published, the astronomical community prefers to read it and the use of e‐prints through the NASA Astrophysics Data System drops to zero. This suggests that most astronomers have access to institutional subscriptions and that they choose to read the journal article. In other words, the e‐prints have not undermined journal use in this community and thus currently do not pose a financial threat to publishers. Furthermore, we show that the half‐life (the point at which the use of an article drops to half the use of a newly published article) for an e‐print is shorter than for a journal paper.