NVDRS is an active, state-based surveillance system that collects information on homicides, suicides, deaths of undetermined intent (i.e., those for which available information is insufficient to enable a medical or legal authority to make a distinction among unintentional injury, self-harm, or assault), deaths from legal intervention (e.g., involving a person killed by an on-duty police officer), and unintentional firearm deaths. Seven states provided data in 2003 (Alaska, Maryland, Massachusetts, New Jersey, Oregon, South Carolina, and Virginia), and six additional states contributed in 2004 (Colorado, Georgia, North Carolina, Oklahoma, Rhode Island, and Wisconsin).
NVDRS uses a multisource approach (i.e., death certificates, coroner/medical examiner reports, law enforcement records, and crime laboratory data) for analysis of violent deaths. Using information from all of these sources, data abstractors in each state assign a manner of death (i.e., suicide, homicide, unintentional firearm deaths, legal interventions, and undetermined deaths) to each case. NVDRS also collects the International Classification of Diseases, 10th Revision (ICD-10) code for underlying cause of death (UCOD), circumstances contributing to the death, and characteristics of the death, including victim-suspect relationship and victim toxicology results. The UCOD is categorized as suicide or homicide using standard definitions from the National Vital Statistics System (NVSS).