Arizona State University (ASU) NUR 452 Concepts in Population-Based Health Exam 1 Practice Test

The main idea is coverage bias from an incomplete sampling frame. When the frame (the list you pull your sample from) underrepresents certain groups, those groups are less likely to appear in the sample. That means the sample doesn’t reflect the population’s true composition, so health estimates (like disease prevalence or risk factors) can be biased toward the groups that are well represented. This is a systematic bias due to undercoverage in the frame, not due to how people respond, how you measure things, or confounding factors.

For example, using a phone-number directory can miss people who don’t have phones or who only use mobile numbers not in the directory, leading to underrepresentation of those groups. This is distinct from nonresponse bias (differences between respondents and nonrespondents), measurement bias (errors in data collection), or confounding bias (an extraneous variable related to exposure and outcome).