Until now, the conventional approach using two distinct groups, experimental and control, continues to dominate research, especially education research. Researchers, particularly those who are active in this domain, readily recognise this pattern when surveying literature. This article explores the use of the Solomon four-group design as a…

This article presents a method to evaluate pretest effects on posttest scores in the absence of an un-pretested control group using published results of pretesting effects due to Willson and Putnam. Confidence intervals around the expected theoretical gain due to pretesting are computed, and observed gains or differential gains are compared with…