Define bias in research.

• A. Error
• B. Bias
• C. Validity
• D. Reliability

Answer: (B)

Bias in research is a systematic deviation from the truth in results or conclusions. It happens when the study design, data collection, measurement, or analysis introduces a distortion that consistently pushes findings in a particular direction. Unlike random error, which fluctuates and can average out with larger samples, bias creates a predictable tilt that threatens the study’s validity. For example, selecting participants in a nonrepresentative way (selection bias) or using a measurement tool that consistently overestimates a value (measurement bias) both introduce bias.

This is why bias is the best fit for defining the concept: it specifically refers to a systematic, directional distortion. The idea of error is broader and includes random mistakes; validity concerns the accuracy of the conclusions, and reliability concerns consistency of results.