Understanding Effect Sizes in Consumer Psychology

Over the past decade, behavioral scientists have learned that many findings in the field may not replicate, leading to calls for change in how behavioral research is conducted. Krefeld-Schwalb and Scheibehenne (2023) examine changes in the methodological practices in consumer research between 2008 and 2020. They find that sample sizes have increased and that effect sizes have decreased. In this article, we take these findings as a starting point and reflect on how we can further improve methodological practices in the field. We argue that in order to build a more replicable, rigorous field, we must place effect sizes at the center of scientific reasoning. Specifically, we make four claims about effect sizes that we hope will help consumer researchers plan, conduct, and interpret their research: (1) effect sizes in consumer psychology are small, and that is a natural consequence of the field’s maturity; (2) effect sizes need to be contextualized; (3) our samples are still too small to detect the small effects of modern empirical consumer research; and (4) larger samples do not inherently generate smaller effects. It is our hope that the current article increases the field’s understanding about effect sizes and motivates researchers to place effect sizes at the center of their scientific reasoning. By thinking carefully about effect sizes, we believe we can collectively improve methodological practices and confidence in the findings of consumer psychology.