The accuracy 1 of population statistics will depend among other factors on the completeness 2 of the count of individuals, groups or events on which they are based. Omissions 3 and undercount 3 tend to generate underestimation 4 while multiple counting 5 leads to over-estimation 6. Additional sources of error include misreporting 7 of a characteristic such as age and classification errors 8. Such inaccuracies are sometimes detected by post-enumeration tests 9 or quality checks 10. Occasionally certain questions are not answered or insufficiently answered and this may lead to considerable inaccuracy, the incidence of which is indicated by the frequency of the class designated as nonresponse 11, not stated 11 or unknown 11.
- 1. Accuracy, n. - accurate, adj.
- 2. Completeness, n. - complete, adj. The terms "complete" and "completeness" are used here to express the absence of omissions. The same terms may also be used to refer to coverage, as in 202-4.
- 3. The omission of some events from vital registration is called underregis-tration, and from a census or survey, underenumeration.
- 5. The expression double counts is often used in this sense.