Colloquium on Effect Sizes: the Roles of Editors, Textbook Authors, and the Publication Manual

Reformers have long argued that misuse of Null Hypothesis Significance Testing (NHST) is widespread and damaging. The authors analyzed 150 articles from the Journal of Applied Psychology ( JAP) covering 1940 to 1999. They examined statistical reporting practices related to misconceptions about NHST, American Psychological Association (APA) guidelines, and reform recommendations. The analysis reveals (a) inconsistency in reporting alpha and p values, (b) the use of ambiguous language in describing NHST, (c) frequent acceptance of null hypotheses without consideration of power, (d) that power estimates are rarely reported, and (e) that confidence intervals were virtually never used. APA guidelines have been followed only selectively. Research methodology reported in JAP has increased greatly in sophistication over 60 years, but inference practices have shown remarkable stability. There is little sign that decades of cogent critiques by reformers had by 1999 led to changes in statistical reporting practices in JAP.