Bias refers to systematic errors that can affect the validity of study results. Common types include:
1. Selection Bias: Occurs when the participants included in the study are not representative of the target population. 2. Information Bias: Results from inaccurate measurement or classification of exposure or disease status. 3. Confounding: Happens when the association between exposure and outcome is distorted by a third variable.
Strategies to manage bias include randomization, blinding, and using statistical methods such as stratification and multivariable analysis.
