Conducting descriptive epidemiology and causal inference studies using observational data: A 10-point primer for stroke researchers.

Routinely-collected health data and emerging data-linkage capabilities provide researchers and clinicians with rich opportunities to answer important research questions by conducting observational studies. We provide stroke researchers with 10 important points to consider and implement to ensure the validity and interpretability of descriptive epidemiology and causal inference studies based on observational data. We discuss different types of observational studies and biases that may arise in such studies. We review types of causal effects and the use of Target Trial emulation and Directed Acyclic Graphs to improve validity of observational studies. We also illustrate appropriate and inappropriate use of covariate adjustment for the analyses of observational studies and review the methods for estimating the effects of treatments, interventions, and exposures in causal inference studies. Finally, we provide recommendations for clinical researchers and journal manuscript reviewers in stroke domain and beyond for the appropriate use and reporting of these methods.