overcounting

Overcounting is the error of recording a quantity that exceeds the true value. It arises when duplicates or ineligible items are included, or when counting units that are not distinct. It is a common concern in statistics, data collection, and accounting, and it is distinct from undercounting, where the observed total falls short of the true count.

In censuses and population surveys, overcounting can occur when individuals are counted more than once due to multiple residences or repeated interviews, or when non-target individuals (non-residents, visitors) are counted as part of the target population.

In inventory management and financial reporting, overcounting can happen from duplicate records, data integration from multiple sources, or counting the same item multiple times due to batch tracking.

Causes include lack of unique identifiers, incompatible data frames, mistakes in data merging, and procedural errors such as recording the same unit under multiple categories.

Consequences include biased estimates, misallocation of resources, inflated performance metrics, and damaged credibility.

Mitigation strategies include de-duplication and record linkage techniques, use of unique identifiers, rigorous data cleaning, validation against independent sources, careful framing of the unit of count, and methods such as capture-recapture to adjust estimates.