Underrapportering

Underrapportering refers to the underestimation of the true extent of a phenomenon because reporting to official data systems is incomplete. It occurs when not all incidents, cases, or observations are recorded, identified, or reported, resulting in statistics that fall short of reality.

Common areas where underrapportering matters include crime statistics, health surveillance, occupational safety, adverse drug reactions, and environmental monitoring. In criminology, a large share of offenses never reaches police records, creating a “dark figure” of crime. In health surveillance, not all illnesses or injuries are reported, leading to undercounts of incidence or adverse events. In workplaces, injuries may go unreported due to fear of repercussions or perceived triviality. In pharmacovigilance, many adverse drug reactions are reported voluntarily and incompletely. In environmental monitoring, emissions or incidents may be undercounted due to limited monitoring. The effects are biased risk estimates, flawed policy, and delayed responses.

Causes of underrapportering include stigma, fear of repercussions, lack of awareness about reporting requirements, and complex or lengthy procedures. Limited resources or infrastructure, fragmented data systems, and differences in definitions or timing can create apparent gaps. These factors interact to produce incomplete data even when incidents occur.

To assess underrapportering, researchers use methods such as data triangulation, capture-recapture, and linkage of multiple registries. Reducing underrapportering involves simplifying reporting processes, mandating or incentivizing reporting, training staff, ensuring feedback to reporters, and linking different data sources to provide a fuller picture. Transparent reporting, standard definitions, and accessible reporting channels can improve data completeness and support better policy and prevention efforts.