American Board of Surgery Qualifying Exam (ABS QE) Practice Test 2026 - Free Surgery Exam Practice Questions and Study Guide

Non-response bias occurs when individuals selected for a study do not participate, which can lead to results that do not accurately represent the population. This type of bias arises specifically from the subset of individuals who choose not to respond or participate in the study, rather than from the way individuals are selected to be part of the study itself. These refusals can skew the data if the non-respondents differ significantly in relevant characteristics from those who do participate. It is particularly concerning in survey research and studies where responses are critical to understanding certain trends or outcomes.

In comparison, selection bias involves the way individuals are chosen to participate in a study, usually leading to a sample that does not reflect the population. Treatment bias refers to differences in treatment allocation that could affect the study's results, while misclassification bias involves errors in assigning participants to groups or categories in a study, which can distort the true association between a variable and an outcome. Non-response bias distinctly focuses on the implications of individuals opting not to engage, setting it apart from these other types of bias.