Retrospective Cohort Studies
Strengths
- Much less costly
- Much less time-consuming
- Advantage over the case-control studies; All of the subjects who developed the outcome (cases) and all those who did not (controls) come from the same population.
Weaknesses
- No control over the nature and the quality of the measurements that were made (e.g., inaccurate, incomplete, less ideal)
- Existing data may not include information that is important to answering the reassert question.
- e.g., Exercise and CHD in Harvard study did not have the data on social support