What best describes a cohort study?

A cohort study is best described as a study that observes and follows people moving forward in time from their entry. This design allows researchers to track the outcomes and behaviors of a specific group, or cohort, over time, providing insights into how various factors may affect outcomes. By starting with a defined group, typically based on a common characteristic or experience, such as age or exposure to a particular treatment, the study can assess changes and outcomes as they occur in real time.

This method is particularly advantageous in identifying potential correlations and causations, as it follows participants prospectively, making it more robust against recall bias and allowing for the assessment of the natural progression of conditions or effects over time. Cohort studies are commonly used in epidemiology to understand risk factors and disease progression.

The other answer choices describe different types of studies. For instance, a study that collects data from a single point in time refers to cross-sectional studies, while comparing outcomes between two separate groups simultaneously describes a case-control study or experimental design. Retrospective studies, on the other hand, analyze data from past records and do not follow participants moving forward in time like cohort studies do.