The extended, lucid treatment of the variety of effect sizes is unique. Also, a helpful page is titled "How to Fool Yourself With Effect Size Estimation." Particularly trenchant are the statements that "generic definitions of effect size magnitude" are problematic, referring to the convention that considers a d index of 0.2 as small, whereas 0.8 is large. It is generally forgotten that the late remarkable innovator, Jack Cohen, proffered these tentative standards as representative of the range of effect sizes common in the psychological literature. He did not address whether this is due to feeble assessments.