ISSN 1671-3710
CN 11-4766/R

Advances in Psychological Science ›› 2020, Vol. 28 ›› Issue (4): 673-680.doi: 10.3724/SP.J.1042.2020.00673

• Research Method • Previous Articles    

What is the minimum number of effect sizes required in meta-regression? An estimation based on statistical power and estimation precision

FANG Junyan, ZHANG Minqiang()   

  1. School of psychology, South China Normal University, Guangzhou 510631, China
  • Received:2019-08-09 Online:2020-04-15 Published:2020-02-24
  • Contact: Minqiang ZHANG


Meta-regression is the most frequently used technique for identifying moderators in meta-analysis. In this study, main principles and basic models of meta-analysis and meta-regression were briefly introduced first. Then a Monte Carlo simulation was conducted to investigate the minimum number of the effect size required in meta-regression based on statistical power and estimation precision. The results showed that (1) the Wald-type z test was prone to type I error in meta-regression; (2) at least 20 effect sizes were needed to meet parameter estimation requirements; (3) and inclusion of proper moderators could reduce the number of effect size required. Therefore, it is suggested that (1) meta-analysts should be careful when using the CMA software and the Wald-type z test; (2) at least 20 or more effect sizes are generally needed based on different situations; (3) exploration of moderators is necessary; (4) reviewers can value a meta-analysis research according to the minimum number of effect size required.

Key words: meta-analysis, meta-regression, effect size, minimum number requirement

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