Post hoc tests following analysis of variance


  • Karyn Holm PhD, RN,

    Associate, Professor, Corresponding author
    • Department of Medical Surgical Nursing, College of Nursing, University of Illinois at Chicago, 845 S. Damen Avenue, Chicago, IL 60612
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    • Dr. Karyn Holm is an associate professor at the University of Illinois, Chicago.

  • Norma J. Christman

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    • Dr. Norma J. Christman is an assistant professor on leave of absence from the University of Illinois. Dr. Christman is currently a post-doctoral fellow in the Department of Behavioral Science, College of Medicine, University of Kentucky.


Review of nursing research literature revealed that post hoc comparisons of mean differences were not consistently reported, although their use was warranted. This paper describes the critical features of post hoc procedures and offers guidelines for selecting one method over another. Particular attention is given to how various procedures control Type 1 error. Selection of post hoc procedures considering the investigator's desire for control of Type 1 and Type 2 error also is presented.