Is Publication Bias Associated With Journal Impact Factor?
Yuan-I Min,1, Aynur Unalp-Arida,2 Roberta Scherer,3and Kay Dickersin4 Objective To evaluate the association between statistically significant results for the primary outcome and the journal impact factor of published clinical trials. Design An existing data set from a retrospective follow-up study (1988-1989) of 3 cohorts of initiated studies evaluating publication bias was used for this analysis. Only trials with full publication (defined as an article with ³3 pages) after study enrollment had been completed, at the time of the follow-up, were included (n = 219). Results for primary outcomes and publication history of the trials were based on investigator interviews. Journal impact factor of published trials was assessed using the 1988 Science Citation Index (impact factors of 0 were assigned to journals not in the Science Citation Index). We used the journal impact factor of the first full publication after study enrollment was completed for all analyses. If more than 1 article was p
