underreporting

Underreporting refers to a discrepancy between the actual occurrence of a phenomenon and the number that is reported or recorded by official data systems. It occurs across many domains, including crime, health, environmental incidents, occupational injuries, tax compliance, and social phenomena. The degree of underreporting can vary over time and by population, complicating efforts to measure incidence and to respond with policy or resources.

Causes include stigma and fear of reprisal (for example in reporting domestic violence or crimes), lack of awareness or understanding of reporting duties, limited access to reporting channels, complex procedures, and concerns about privacy or data use. In proactive contexts, incentives or sanctions, or perceived consequences, can also influence whether individuals or institutions report events. Additionally, administrative capacity constraints and resource limitations can hinder data collection and processing, leading to underrecording.

Consequences include biased estimates of prevalence, misinformed policy decisions, misallocation of resources, and an incomplete understanding of risk factors. Underreporting can mask emerging problems and undermine surveillance systems, research, and evaluation efforts. Some domains face particular challenges; for example, in pharmacovigilance, only a fraction of adverse drug reactions are reported; in crime statistics, many incidents go unreported to authorities.

Measurement and estimation methods to address underreporting include survey techniques that reduce social desirability bias, indirect estimation methods such as capture-recapture, triangulation of multiple data sources, sentinel surveillance, and statistical adjustments. Improving data quality involves confidentiality assurances, user-friendly reporting platforms, mandatory reporting where appropriate, training, and outreach to affected populations to build trust.

Policy implications emphasize transparency, data integration, and robust monitoring frameworks. While underreporting is often unavoidable to some degree, acknowledging its presence is essential for accurate assessment and effective intervention.