Blinding aims to limit conscious and unconscious bias in which areas?

• A. Blinding has no impact on recruitment or data handling.
• B. It aims to limit conscious and unconscious bias in recruitment, allocation, care, endpoint assessment, withdrawals, and data handling.
• C. It only affects data analysis.
• D. It is primarily used to protect sponsor interests.

Answer: (B)

Blinding prevents both conscious expectations and subconscious influences from shaping how a trial proceeds and how outcomes are judged. By keeping participants, clinicians, and assessors unaware of the assigned treatment, bias is reduced across multiple stages: recruitment decisions and eligibility judgments; allocation and concealment to prevent predictable assignment; the care provided to participants to avoid differential treatment; the assessment of endpoints so outcomes aren’t judged in light of treatment knowledge; participants’ decisions to withdraw or continue; and how data are handled, analyzed, or reported. This broad protection helps preserve the trial’s integrity and validity, not just a single aspect.

Other choices misstate the scope of blinding. It does matter for recruitment and data handling, not just data analysis, and it isn’t primarily about protecting sponsor interests.