Effect Modification

  • Bryan Kestenbaum


The impact of an exposure or treatment may differ across people. Effect modification occurs when the size of an association between an exposure and outcome differs according to another characteristic. A true differential impact of an exposure or treatment on the disease process is suspected when the difference in the size of an association across subgroups is large, the subgroups contain sufficient numbers of people and outcomes for comparison, there is plausibility for the observed difference, and the difference is replicated in other studies. Non-overlapping confidence intervals and a low p-value for interaction provide statistical evidence for the presence of effect modification.

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Bryan Kestenbaum
    • 1
  1. 1.Division of Nephrology, Department of MedicineUniversity of WashingtonSeattleUSA

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