Final answer:
A case-control study compares a group of subjects having a trait of interest with a group of similar subjects not having the trait retrospectively. A retrospective cohort study is a study where a group of similar subjects is selected at the start and followed over time. The selection of one approach over the other depends on the research question, feasibility, cost, and data availability.
Step-by-step explanation:
A case-control study is a type of observational study that compares a group of subjects having a trait of interest (cases) with a group of similar subjects not having the trait (controls). This type of study is retrospective, meaning that subjects are asked to report their behaviors in the past to find correlations between specific past behaviors and current status.
A retrospective cohort study, on the other hand, is an observational study in which a group of similar subjects (the cohort) is selected at the start of the study and then followed over time. This type of study is prospective, meaning that the researchers collect data on the cohort periodically into the future.
The key criteria that can influence the selection of one approach over the other include the research question, feasibility, cost, and the availability of data. Case-control studies are generally faster and less expensive, making them more suitable for rare diseases or conditions and when it is difficult to follow a large cohort over time. On the other hand, cohort studies allow for the assessment of multiple outcomes and provide stronger evidence for causality.