Which of the following study designs is most likely to involve prospective data collection?

Cohort studies are characterized by their design, which involves following a group of individuals forward in time to observe outcomes as they occur. In a cohort study, researchers select participants based on their exposure status (exposed or unexposed to a specific factor), and then collect data on outcomes over time. This prospective approach allows for the direct observation of how exposures can affect the risk of developing a condition or disease, making it particularly valuable in establishing causal relationships.

In contrast, cross-sectional studies collect data at a single point in time, which does not allow for the tracking of outcomes as they develop. Case-control studies are retrospective and begin with an outcome, looking back to determine exposure, thus not involving prospective data collection. Retrospective studies also analyze existing data from the past, focusing on outcomes and tracing back to exposures.

Thus, the cohort study's framework of collecting data on exposures before the outcomes occur makes it the design most likely to involve prospective data collection.