Stratification analysis is used to to identify predictive biomarkers. For example, markers able to predict the response to a drug. These markers are fundamental to precision medicine approaches and is the basis of companion diagnostic tests.
In addition the the predictive markers, stratification is also used for the identification of prognostic biomarkers. That is, markers able to predict the evolution of a disease. Prognostic markers provide interesting insights in key disease mechanisms, not necessarily linked to drug treatment.
Both predictive and prognostic markers contribute to increase knowledge on the drug and the underlying disease mechanisms, bringing value to clinical development projects. Ultimately stratification analyses aim at identifying the most adapted drugs to a group of patients.