A Simple Effect Size Indicator for Two-Group Comparisons? A Comment on requivalent.

R. Rosenthal and D. B. Rubin (2003) proposed an effect size, r equivalent, to be used when (a) only sample size and p values are known for a study, (b) there are no generally accepted effect size indicators, or (c) sample sizes are so small or the data so non-normal that the directly computed effect sizes would be more misleading than the simple effect size. The limitations of their proposal, however, are many, and much more serious than the...