The term coverage, as used in survey research, indicates how well the sampling units included in a particular sampling frame account for a survey's denned target population. If a sampling frame does not contain all the units in the target population, then there is undercoverage of the population. If the frame contains duplicate units or other units beyond those contained in the population, then there is overcoverage. Undercover-age and overcoverage do not necessarily mean there will be coverage error associated with the frame.

Overcoverage occurs when members of the survey population are erroneously included in the survey sampling frame more than once or are included erroneously. Noncoverage (including undercoverage) occurs when members of the targeted population are erroneously excluded from the survey sampling frame. The meaning ...