Final answer:
A prospective cohort study is an observational study that follows a specific group of individuals over time to observe outcomes, gathering more precise data since it tracks the population moving forward. It's more costly and extensive in duration compared to other observational studies such as case-control and cross-sectional studies.
Step-by-step explanation:
A prospective cohort study is a type of observational study where a group of individuals, known as a cohort, is followed over time to observe and record the occurrence of specific outcomes. This kind of study begins with the selection of a cohort based on shared characteristics and tracks the subjects moving forward in time, gathering data at various intervals. One of the major advantages of this design is the ability to determine the sequence of events leading up to the outcomes, with data likely being more accurate since it's obtained directly rather than relying on participants' recall. However, these studies are known to be investments in terms of time and cost, as they may span several months to years. A prospective cohort study contrasts with other types of observational studies like retrospective case-control studies (where past behaviors and outcomes are compared), and cross-sectional studies (where data is collected from a sample at a single point in time).