The Continuing Problem of False Positives in Repeated Measures ANOVA in Psychophysiology: A Multivariate Solution

Authors

  • Michael W. Vasey,

    1. Department of Psychology, The Pennsylvania State University, University Park, Pennsylvania
    Search for more papers by this author
  • Julian F. Thayer

    Corresponding author
    1. Department of Psychology, The Pennsylvania State University, University Park, Pennsylvania
      Address requests for reprints to: Julian F. Thayer, Department of Psychology, The Pennsylvania Stale University, University Park, Pennsylvania 16802.
    Search for more papers by this author

  • The authors wish to thank Robert Stern, Ralph O'Brien, and Robert Kennedy for their helpful comments.

  • A shorter version of this paper was presented at the thirteenth meeting of the Psychophysiology Society, London, December, 1985.

Address requests for reprints to: Julian F. Thayer, Department of Psychology, The Pennsylvania Stale University, University Park, Pennsylvania 16802.

ABSTRACT

Violation of the validity assumptions of repeated measures analysis of variance continues to be a problem in psychophysiology. Such violation results in positive bias for those tests involving the repeated measures factor(s), Recently it has been shown that the tests of simple interactions and multiple comparisons are even more vulnerable to bias (Boik. 1981; Mitzel & Games, 1981). The present paper offers a discussion of the validity assumptions for both overall and sub-effect tests and describes a multivariate approach which allows exact analysis of such designs. A modification of the univariate approach is also described. Validity concerns for both approaches are much less problematic than those of the traditional approach.

Ancillary