ISSN 1671-3710
CN 11-4766/R

›› 2011, Vol. 19 ›› Issue (12): 1868-1878.

• 研究方法 • Previous Articles    

The Appropriate Effect Sizes and Their Calculations in Psychological Research

ZHENG Hao-Min;WEN Zhong-Lin;WU Yan   

  1. (1 Center for Studies of Psychological Application, South China Normal University, Guangzhou 510631, China)
    (2 Department of Applied Psychology, Guangdong University of Foreign Studies, Guangzhou 510420, China)
  • Received:2010-11-10 Revised:1900-01-01 Online:2011-12-15 Published:2011-12-15
  • Contact: WEN Zhong-Lin

Abstract: Effect sizes are important supplement of the null hypothesis significance testing. More and more academic journals request authors provide the effect sizes of their researches. Our purpose is to provide a guideline on how to compute the appropriate effect sizes of different researches and data types. We classified the effect sizes into three types, including difference-type, correlation-type and group-overlap. For each type of the effect sizes, there are different approaches of calculations and applications under different research designs (e.g., single-factor/multifactor between-subjects, single-factor/multifactor within-subjects) and data conditions (e.g., small sample size, heterogeneity of variance). Many effect sizes, however, can be transformed from one type to another. We summarized a table that may help readers to choose appropriate effect sizes for their researches based on the research purposes and research designs.

Key words: effect size, difference-type, correlation-type, group overlap-type