Standard Article

Kruskal-Wallis Test

  1. Patrick E. McKight,
  2. Julius Najab

Published Online: 30 JAN 2010

DOI: 10.1002/9780470479216.corpsy0491

Corsini Encyclopedia of Psychology

Corsini Encyclopedia of Psychology

How to Cite

McKight, P. E. and Najab, J. 2010. Kruskal-Wallis Test. Corsini Encyclopedia of Psychology. 1.

Author Information

  1. George Mason University

Publication History

  1. Published Online: 30 JAN 2010


The Kruskal-Wallis (Kruskal & Wallis, 1952) is a nonparametric statistical test that assesses the differences among three or more independently sampled groups on a single, non-normally distributed continuous variable. Non-normally distributed data (e.g., ordinal or rank data) are suitable for the Kruskal-Wallis test. In contrast, the one-way analysis of variance (ANOVA), which is a parametric test, may be used for a normally distributed continuous variable. The Kruskal-Wallis test is an extension of the two-group Mann-Whitney U (Wilcoxon rank) test. Thus, the Kruskal-Wallis is a more generalized form of the Mann-Whitney U test and is the nonparametric version of the one-way ANOVA.


  • ANOVA;
  • nonparametric;
  • ranks