Synthesizing standardized mean‐change measures

A new approach is presented for the meta‐analysis of data from pre‐test‐post‐test designs. With this approach, data from studies using different designs may be compared directly and studies without control groups need not be omitted. The approach is based on a ‘standardized mean‐change’ measure, computed for each sample within a study, and involves analysis of the standardized mean changes and differences in the standardized mean changes. Analyses are illustrated using results of studies of the effectiveness of mental practice on motor‐skill development.