Dietrich, JP (2008) Disentangling visibility and self-promotion bias in the arXiv: astro-ph positional citation effect. PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC 120 (869): 801-804
Abstract: We established in an earlier study that articles listed at or near the top of the daily arXiv:astro-ph mailings receive on average significantly more citations than articles further down the list. In our earlier work we were not able to decide whether this positional citation effect was due to author self-promotion of intrinsically more citable papers or whether papers are cited more often simply because they are at the top of the astro-ph listing. Using new data we can now disentangle both effects. Based on their submission times we separate articles into a selfpromoted sample and a sample of articles that achieved a high rank on astro-ph by chance and compare their citation distributions with those of articles in lower astro-ph positions. We find that the positional citation effect is a superposition of self-promotion and visibility bias.
This interesting paper reports that in the physics Arxiv (astrophysics sector), where virtually all current articles in astrophysics are OA in preprint form (with no postprint OA problem in astrophysics either) several factors significantly influence citation counts:
(1) Arxiv provides a daily list of articles deposited. The articles higher on that list are more cited than the articles lower on that list.
(2) Whether an article appears higher on that list does not depend on merit. It depends on what time the article was deposited.
(3) Timing is predictable from time zones and geography, so if these two factors are controlled for, one can also identify which articles were (probably) deliberately timed by their authors so as to appear near the top of the list (“self-promotion”).
(4) This study shows that even after one has removed any effect of self-promotion, appearing nearer the top of the list randomly still increases an article’s citation count.
(5) In addition, self-promotion itself increases an article’s citation count too. (The assumption is that the more self-promoted papers are better, hence more likely to have higher citation counts; this may or may not be the only or main reason why self-promotion further increases citations over and above the list position effect.)
The authors rightly point out that in a high-output field like astrophysics, visibility is an important factor in usage and citations, and authors need alerting and navigation aids based on importance, relevance and quality, rather than on random timing and author self-promotion biasses.
I would add that in fields — whether high- or low-output — that, unlike astrophysics, are not yet OA, accessibility itself probably has much the same sort of effect on citations that visibility does in an OA field like astrophysics. (Even maximized visibility cannot make articles accessible to those who cannot afford access to the full-text.)