##  [Effect Modification](/effect-modification) 

  ##  [Effect Modification](https://health.quantumdictionary.io/effect-modification-0) 

  

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**Health & Life Sciences Dictionary**

 







 

 

 

 



 

 

 

 

Definition

A situation in which the magnitude or direction of the effect of an exposure on an outcome differs across levels or categories of a third variable (the effect modifier); this heterogeneity reflects true variation in effect rather than bias.