Undercoverage is statistical bias that occurs when some groups in a target population are omitted or systematically underrepresented by the sampling frame. Because the omitted units have no or reduced chance of selection, increasing the sample size within the same frame does not remove undercoverage.
Undercoverage
See also
Nonresponse Bias, Population, Sample Size, Sampling, Statistical BiasExplore with Wolfram|Alpha
References
Cochran, W. G. Sampling Techniques, 3rd ed. New York: Wiley, 1977.Cite this as:
Weisstein, Eric W. "Undercoverage." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Undercoverage.html