Reporting Practices and APA Editorial Policies Regarding Statistical Significance and Effect Size

Abstract

The recent fourth edition of the American Psychological Association Publication Manual emphasized that p values are not acceptable indices of effect and `encouraged' effect-size reporting. However, empirical studies of reporting practices of diverse journals unequivocally indicate that this new encouragement has to date been ineffective. Here two additional multi-year studies of APA journals are reported. Additionally, all 50 APA editorials that have been published since 1990 were reviewed to determine how many editors with approval have articulated policies more forceful than the APA Publication Manual's vague and seemingly self-canceling encouragement. It is suggested that changes in editorial policies will be required before improved reporting will become routine.