Epidemiology is a fundamental discipline in medical research, as it examines the distribution and determinants of diseases within populations. To achieve this, it employs various research designs, which are broadly classified into observational and experimental studies. Observational studies include descriptive studies, such as case series and cross-sectional studies, as well as analytical studies, such as cohort and case-control studies, which assess associations between exposures and health outcomes. Experimental studies, particularly randomized controlled trials, establish causal relationships. The choice of study design depends on the research question, feasibility and available resources. It is essential to understand their characteristics, the contexts in which they should be applied and the most common sources of bias to ensure the accurate interpretation of results.
Pérez‐Moneo et al. (2025) studied this question.