How can detection and performance biases be eliminated in animal trials?

• A. By increasing sample size.
• B. By blinding owners and clinicians to treatment status.
• C. By using surrogate endpoints.
• D. By randomizing only one group.

Answer: (B)

Blinding the people who handle the animals, administer treatments, and assess outcomes to which animals received the experimental treatment minimizes both detection and performance biases. When those involved don’t know which animals got the treatment, care is delivered more uniformly and outcome measurements are less likely to be influenced by expectations. This reduces the chance that differences in results are due to how animals are treated or how outcomes are interpreted, rather than true effects of the intervention. In practice, masking treatment status and using objective, automated endpoints where possible further strengthens this protection.

Increasing sample size helps with random error but doesn’t remove systematic bias. Surrogate endpoints may misrepresent true effects if they don’t perfectly reflect meaningful outcomes. Randomizing only one group introduces bias and undermines comparability.