caseseries

A case series is a descriptive study design used in medical and health research that collects and analyzes data from a group of patients who share a common condition, treatment, or exposure. Unlike studies with control groups, a case series does not test hypotheses through randomization or comparative analysis; instead it aims to describe clinical features, management approaches, and outcomes across multiple cases.

Case series can be retrospective, prospective, or a combination of both, and they may be conducted within a single institution or across multiple centers. They are often used to document rare diseases, novel therapies, unusual adverse events, or early experiences with a new diagnostic or surgical technique. The findings are typically summarized using descriptive statistics such as frequencies, percentages, and timelines, sometimes supplemented by narrative synthesis.

Limitations of case series include susceptibility to selection bias, lack of a control group, and limited generalizability to broader populations. Because they do not assess causality, conclusions about effectiveness or risk are inherently weak and should be interpreted with caution. Case series are most valuable as exploratory evidence that can generate hypotheses and justify more rigorous studies, such as controlled cohorts or randomized trials.

Reporting a case series generally requires clear documentation of how cases were identified and selected, the data collection methods, the outcomes observed, and the duration of follow-up, with attention to patient privacy and consent where applicable.