Bias is an error that distorts the objectivity of a study and affects the results. It can arise when researchers do not follow rigorous standards in study design, subject selection, treatment administration, data analysis, or reporting and interpretation. Bias can also result from circumstances beyond a researcher’s control, such as uneven distribution of participant characteristics between groups due to randomization or data collection.
Synonyms:
Distortion, Partiality
Example
Selection Bias: A clinical trial on a new arthritis medication recruits only younger participants with mild symptoms. This group is not representative of the wider population of people with arthritis, so the results overestimate the drug’s effectiveness.
Response Bias: In a survey about alcohol consumption, respondents under-report how much they drink to appear healthier or more socially acceptable.