Which strategies help minimize experimental bias?

• A. Relying on a single observer
• B. Blinding, randomization, controls, and replication
• C. Ignoring randomization
• D. Post-hoc data mining

Answer: (B)

Minimizing experimental bias means arranging the study so that the results truly reflect the treatment’s effect rather than anyone’s expectations or random chance. Blinding keeps researchers and participants unaware of which treatment is given, so measurements and judgments aren’t swayed by expectations. Randomization places subjects or samples into groups by chance, ensuring the groups are comparable and reducing confounding factors that could skew outcomes. Controls provide a baseline or standard for comparison, helping to isolate the treatment effect from other influences. Replication repeats the experiment or its measurements, giving a reliable estimate of variability and confirming that the results aren’t just a fluke. Put together, these practices guard against bias from expectations, selection of subjects, placebo effects, and random error, leading to more trustworthy conclusions. The other options fall short because relying on a single observer introduces judgment bias, ignoring randomization allows systematic differences between groups, and post-hoc data mining can produce spurious findings rather than robust evidence.