To identify effect modifiers, researchers often stratify their data by the potential effect modifier and then examine the association between exposure and outcome within each stratum. If the association differs significantly between strata, the variable is considered an effect modifier.
Steps to Identify Effect Modifiers:
1. Stratification: Divide your dataset based on the potential effect modifier. 2. Examine Associations: Calculate the association between exposure and outcome within each stratum. 3. Compare Results: Compare the strength and direction of associations across strata. 4. Statistical Interaction: Use statistical tests, such as interaction terms in regression models, to formally assess effect modification.
