Statistical Reform in Psychology

We investigated whether statistical practices in psychology have been changing since 1998. Early in this period, the American Psychological Association (APA) Task Force on Statistical Inference (TFSI; Wilkinson & TFSI, 1999) advocated improved statistical practices, including reporting effect sizes and confidence intervals (CIs). The APA (2001) Publication Manual included expanded advice on effect sizes and stated that CIs are ‘‘in general, the best reporting strategy’’ (p. 22). Any changes since 1998 may, of course, have had many causes other than those two sources of advice.