This article analyses the difference in timing between the online
availability of articles and their corresponding print publication and how it
affects two bibliometric indicators: Journal Impact Factor (JIF) and Immediacy
Index. This research examined 18,526 articles, the complete collection of
articles and reviews published by a set of 61 journals on Urology and
Nephrology in 2013 and 2014. The findings suggest that Advance Online
Publication (AOP) accelerates the citation of articles and affects the JIF and
Immediacy Index values. Regarding the JIF values, the comparison between
journals with or without AOP showed statistically significant differences
(P=0.001, Mann-Whitney U test). The Spearman's correlation between the JIF and
the median online-to-print publication delay was not statistically significant.
As to the Immediacy Index, a significant Spearman's correlation (rs=0.280,
P=0.029) was found regarding the median online-to-print publication delays for
journals published in 2014, although no statistically significant correlation
was found for those published in 2013. Most journals examined (n=52 out of 61)
published their articles in AOP. The analysis also showed different publisher
practices: eight journals did not include the online posting dates in the
full-text and nine journals published articles showing two different online
posting dates--the date provided on the journal website and another provided by
Elsevier's Science Direct. These practices suggest the need for transparency
and standardization of the AOP dates of scientific articles for calculating
bibliometric indicators for journals
