Effect Size Reporting Practices in Published Articles

Findings indicate no major differences between the two types of journals in terms of ES reporting practices, and different conclusions could be reached based on interpreting ES versus p values.

Abstract

Effect size (ES) reporting practices in a sample of 10 educational research journals are examined in this study. Five of these journals explicitly require reporting ES and the other 5 have no such policy. Data were obtained from 99 articles published in the years 2003 and 2004, in which 183 statistical analyses were conducted. Findings indicate no major differences between the two types of journals in terms of ES reporting practices. Different conclusions could be reached based on interpreting ES versus p values. The discrepancy between conclusions based on statistical versus practical significance is frequently not reported, not interpreted, and mostly not discussed or resolved.