Bias is a systematic error that can distort the results of an epidemiological study. It can arise from several sources, including selection bias, information bias, and confounding. Selection bias occurs when the participants included in a study are not representative of the target population. Information bias results from errors in measuring exposure or outcome. Confounding occurs when the relationship between an exposure and an outcome is influenced by an external factor. Researchers must identify and correct for biases through study design and statistical adjustments.
