JAMA Guide to Statistics and Methods
August 6, 2014

Multiple Comparison Procedures

Author Affiliations
  • 1Department of Statistical Science, Southern Methodist University, Dallas, Texas
  • 2Department of Clinical Sciences, UT Southwestern Medical Center, Dallas, Texas

Copyright 2014 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.

JAMA. 2014;312(5):543-544. doi:10.1001/jama.2014.9440

Problems can arise when researchers try to assess the statistical significance of more than 1 test in a study. In a single test, statistical significance is often determined based on an observed effect or finding that is unlikely (<5%) to occur due to chance alone. When more than 1 comparison is made, the chance of falsely detecting a nonexistent effect increases. This is known as the problem of multiple comparisons (MCs), and adjustments can be made in statistical testing to account for this.1

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