Biostatistics & Study Design USMLE Step 1 Practice Question
A nested case control study of venous thromboembolism is conducted within a large cohort of women using oral contraceptives. Each time a new thrombosis case occurs, controls are selected from women who are still at risk in the cohort at that same time point. Which sampling strategy is being used?
Answer choices
- ASnowball sampling
- BIncidence density samplingCorrect answer
- CEcologic sampling
- DSimple random sampling from the full cohort at baseline
- EConvenience sampling
- FDensity of disease sampling stratified by exposure status
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.