The impact factors of nearly 200 open-access journals are similar to those of traditional journals in the same fields, according to a recent Thomson ISI report. The 58 open-access medical journals that receive impact factors fell, on average, at the 40th percentile of all medical journals, with all but 11 ranking higher than the 10th percentile. For life sciences journals, the 37 open-access journals were ranked, on average, at the 39th percentile.
Since the percentile indicates the journal's rank within its discipline, 50th percentile is literally average, according to James Pringle, vice president for Development in Academic and Government Markets for Thomson ISI.
Pringle said that the results might also disappoint some proponents of open access, who believed that researchers would cite freely available information more often than papers published in traditional journals. The report may be “good news to all sides of the debate,” Pringle told