Participation bias or non-response bias is a phenomenon in which the results of studies, polls, etc. become non-representative because the participants disproportionately possess certain traits which affect the outcome. These traits mean the sample is systematically different from the target population, potentially resulting in biased estimates.[1]
For instance, a study found that those who refused to answer a survey on AIDS tended to be "older, attend church more often, are less likely to believe in the confidentiality of surveys, and have lower sexual self disclosure."[2] It may occur due to several factors as outlined in Deming (1990).[3]
Non-response bias can be a problem in longitudinal research due to attrition during the study.[4]
{{cite book}}
: CS1 maint: location missing publisher (link)