Which approach is used to avoid bias in experiments?

• A. Randomization of subjects
• B. Blind and double blind controls
• C. Placebo control
• D. Control group

Answer: (B)

Bias in experiments comes from expectations shaping how people behave, respond, or how measurements are recorded. Blind studies help because participants don’t know which treatment they’re getting, so their expectations can’t distort their responses. Double-blind takes this further: neither the participants nor the researchers interacting with them know who is receiving which treatment. This stops subconscious cues, differences in treatment, or how data are collected from influencing the results. Together, these steps provide the strongest protection against bias by preventing both participant and observer influences on the outcome.

Randomization helps make groups comparable by spreading unknown factors randomly, which reduces selection bias, but it doesn’t directly prevent bias in how outcomes are measured. A placebo control accounts for placebo effects, but without blinding, expectations can still creep in. A control group gives a baseline for comparison but doesn’t by itself stop bias unless paired with blinding.

So, implementing blind and double-blind controls is the most effective way to avoid bias in experiments.