What type of study takes multiple patients and describes their experiences without testing a hypothesis?

A case series is a type of observational study that focuses on a group of patients who share a common characteristic or experience. In this context, the study describes their outcomes or experiences, often highlighting new or unusual phenomena, without testing a specific hypothesis as would occur in experimental studies.

In a case series, researchers compile and summarize clinical data from multiple individuals, which provides insight into patterns of disease, potential outcomes, or responses to treatment, but it does not involve a controlled comparison group, nor does it aim to establish causation. This approach is particularly useful in the early stages of understanding a disease or condition, where there may be limited data available.

Other study types listed, such as cross-sectional surveys, control studies, and cohort studies, typically involve testing a hypothesis or making comparisons between different groups, which distinguishes them from a case series.