Results everyone can understand: A review of common language effect size indicators to bridge the research-practice gap.

Abstract

Health psychology, as an applied area, emphasizes bridging the gap between researchers and practitioners. While rigorous research relies on advanced statistics to illustrate an underlying psychological process or treatment effectiveness, these statistics have less immediate applicability to practitioners who require knowing the relative magnitude in practical benefits. One way to reduce this research-practice gap is to translate reported effects into nontechnical language whose focus is on the likelihood of benefiting an individual. Common Language Effect Size (CLES) indicators offer a more intuitive way to understand statistical results from research but may not be widely known to researchers. This article synthesizes the literature of available CLES indicators and how they overcome limitations from traditional effect sizes. To promote adoption, we summarize all existing measures in a compact table, which includes their analogous effect size, context, interpretation, calculation, and citation. We present evidence describing the effectiveness of CLES indicators at facilitating research interpretability compared to traditional effect size indicators. We discuss some limitations of CLES indicators and reasons that they are not used in psychology. Finally, this review offers some future directions for the use and study of CLES indicators moving forward. In general, CLES indicators are tools that can benefit health psychology because of their shared goals to aid practitioners in understanding research findings and making informed decisions. (PsycInfo Database Record (c) 2021 APA, all rights reserved).