In a trial, the person allocating participants cannot know the next allocation in advance. Which bias does this concealment of allocation reduce?
Answer and explanation
Correct answer: A. Selection bias
- Step 1: Knowing the next allocation lets recruiters steer patients.
- Step 2: Concealment protects randomisation, whereas blinding reduces performance and detection bias.
Answer
Selection bias.
Why not the others: Observer bias: Observer bias is reduced by blinding of assessors. Recall bias: Recall bias is about memory. Publication bias: Publication bias concerns reporting of studies.
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