To conduct stratified analysis, follow these steps:
Identify potential confounders or effect modifiers. Divide the data into strata based on these variables. Calculate the measure of association (e.g., odds ratio, risk ratio) within each stratum. Compare the measures of association across strata to determine if they are consistent or if there is evidence of effect modification. If consistent, combine the stratum-specific estimates using techniques such as the Mantel-Haenszel method.
