A Comment on Gonzalez's “Effects of a Theory-Based,Peer-Focused Drug Education Course”

Gonzalez (1990), in an unequal-groups quasiexperiment drug education study, stated that because he used the statistical procedure of analysis of covariance, any differences that existed in the pretest scores have been controlled. Not true. This makes his results difficult to interpret. Furthermore, no standard deviations or pretest means are reported, and, thus, no effect size can be calculated to include the results of this study in a meta-analysis.