EPI 390 Study Guide - Final Guide: Recall Bias, Cohort Study, Confounding
Document Summary
Hospital based case control studies are prone to selection bias. More sick people in the hospital than the rest of the population. Form of selection bias in case control studies attributed to selective survival among the prevalent cases. Observation bias can result form differential accuracy of recall between cases and controls(recall bias). Recall bias can occur because cases have spent more time pondering why they became cases and have better recall of their exposure status than other people. Occurs when exposure or disease status is inaccurately assigned. Observation bias resulting from differential recall between cases and controls. **results in over or underestimation of true association. Similar level of inaccurate assignment of exposure status exists between cases and controls. ***always will result in underestimation of true association. Occurs when an extrinsic factor is associated with a disease outcome and independent of that association is also associated with the exposure.
