Overcoverage occurs in survey sample frames when the frame contains more than enough sample records. This primarily results from two situations. In one case, there are records in the sample frame that do not contain respondents or members of the target population. In other cases, the same respondent is targeted by duplicate or multiple records in the sample frame. In either case, the sample frame contains sample records that should be interviewed.

Different types of overcoverage are commonly referred to as "ineligible units" or "multiple records." Different researchers use the term overcoverage inconsistently, so it is important to consider whether over-coverage in a given sample frame is caused by ineligible units, multiple records, or both.

Sample frames ideally contain a perfect one-to-one correspondence between sample records and ...