Abstract
The Publication Manual of American Psychological Association (APA manual, 2009) indicates that all articles must report the effect sizes in the "Result" section of the study. However, few nursing research articles report the effect sizes as a study result. This study investigates whether nursing research articles in Japan report the effect sizes for results of statistical analyses. The subjects of this study were 186 articles published from 2012 to 2016 in "Journal of Japan Society of Nursing Research" I investigated whether articles using t-test in this journal reported the effect sizes of d-family (i.e., the effect size for t-test. For example, Cohen's d, Hedges' g, gadj, and Glass' Δ) as a result of analysis. A total of 25 articles performed the t-test for statistical analysis. However, none of these articles reported the effect size of d-family. Only one study reported the partial correlation ratio (η) as the effect size. This result suggests that Japanese nursing researchers do not recognize the importance of reporting effect sizes in their studies. To accurately discuss the results of nursing research, all researchers need to understand the properties of effect sizes and report them in articles.
