More Powerful Tests of Simple Interaction Contrasts in the Two-Way Factorial Design

Gregory R. Hancock, Daniel McNeish

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


For the two-way factorial design in analysis of variance, the current article explicates and compares three methods for controlling the Type I error rate for all possible simple interaction contrasts following a statistically significant interaction, including a proposed modification to the Bonferroni procedure that increases the power of statistical tests for deconstructing interaction effects when they are of primary substantive interest. Results indicate the general superiority of the modified Bonferroni procedure over Scheffé and Roy-type procedures, where the Bonferroni and Scheffé procedures have been modified to accommodate the logical implications of a false omnibus interaction null hypothesis. An applied example is provided and considerations for applied researchers are offered.

Original languageEnglish (US)
Pages (from-to)24-35
Number of pages12
JournalJournal of Experimental Education
Issue number1
StatePublished - Jan 2 2017
Externally publishedYes


  • Analysis of variance
  • factorial designs
  • interactions
  • pairwise interaction contrasts
  • simple interaction contrasts
  • Type I error

ASJC Scopus subject areas

  • Education
  • Developmental and Educational Psychology


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