Tort ABL, Targino ZH, Amaral OB. Rising publication delays inflate journal impact factors. PLoS ONE 2012;7(2):e53374
In this study the authors used publication records of neuroscience journals to analyze the evolution of publication delay over the last decade, and to study whether this phenomenon can alter journal impact factors. They showed that online-to-print lags (that is, the delay between online availability of an article and its print publication) have risen steeply in recent years, and that they led to earlier citations, and thus to an increase in impact factors. According to the authors, a simple means to avoid distortions such as the one described is the indexing of articles by scientific databases on the date of their online appearance, rather than on that of their publication in print.