Biostatistics & Study Design USMLE Step 1 Practice Question
A multicenter hypertension trial finds that a small number of blood pressure readings are missing because some laboratory printouts were accidentally destroyed in a flood affecting one storage room. The loss was unrelated to patient characteristics, treatment assignment, or blood pressure values. Which description best fits this missing data mechanism?
Answer choices
- ADifferential misclassification
- BConfounding
- CMissing not at random
- DMissing completely at randomCorrect answer
- EImmortal time bias
- FSelection bias
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.