Overview: The session will start with a detailed examination of various tools to control for confounding, emphasizing multivariable analysis techniques. Participants will also learn the basics of propensity score methods, including propensity score matching, stratification, and weighting. The latter part of the course will introduce the target trial framework, a conceptual approach that aims to design observational studies in a way that emulates a hypothetical randomized controlled trial. This framework provides a structured methodology for causal inference, offering a robust way to draw conclusions about cause-and-effect relationships in real-world headache research settings. By the end of this course, participants will understand how to apply these advanced methods to enhance the validity of their epidemiological studies on headache disorders.