Measurement Issues: Large effect sizes do not mean most people get better: Clinical significance and the importance of individual results
Child and Adolescent Mental Health
Background This paper seeks to compare group statistical analysis with effect size, group measures of clinical significance (Reliable Change Index and normative comparison), and individual analysis of clinical significance. Method Measures of variables important to parenting and child behavior improvement (Parenting Scale, Eyberg Child Behavior Inventory, and Parenting Stress Index [PSI]) were administered pre and post for a 9- to 10-week group Behavioral Parent Training Intervention. Analysis compares traditional group statistical significance testing with group measure of clinical significance and individual analysis of clinical significance. Results All three measures demonstrated statistically significant differences from pre to post, with large effect sizes. Group measures of clinical significance, however, demonstrated meaningful change only on the PSI, while individual analysis showed improvements of 54% of participants at best and 0% at worst. Conclusions Individual analysis of clinical significance provides valuable information in treatment outcomes and should be included as a standard practice in outcomes research.
Jensen, S. A., & Corralejo, S. M. (2016). Measurement Issues: Large effect sizes do not mean most people get better: Clinical significance and the importance of individual results. Child and Adolescent Mental Health, 22, 163-166. doi:10.1111/camh.12203