Question: Pairwise comparisons, effect size, and significance. Volker (2006) stated the following in an article describing recommendations for the use of effect size in school psychology research: "Report at least one measure of effect size for each major [pairwise] comparison it is probably best to report only effect size results for comparisons that are statistically significant" (p. 670). Explain why it is not necessary to report effect size estimates for results that are not significant.