Eligibility

Eligibility refers to whether or not a sampled unit is eligible to have data gathered from it—that is, is the unit part of the survey's target population or is it not? For example, the target population for a survey might be all adults who are 18-34 years of age. As such, if a household is sampled and screened via random-digit dialing and no one living there fits the age criteria, then the household is ineligible. If there is at least one person ages 18-34 years, then the household is eligible. Ultimately, eligibility versus ineligibility is central to the issue of how well a sampling frame and a sample drawn from that frame "cover" the target population and whether or not coverage error results. Eligibility also ...