Context: Maryland began a statewide firearm-related injury surveillanc
e system in 1995. The system now focuses on firearm-related deaths; a
system to monitor nonfatal injuries is being developed. The system is
passive; it accesses, integrates, and analyzes data collected by il Ma
ryland's Office of the Chief Medical Examiner, Maryland State Police,
and Division of Health Statistics. Objective: To evaluate the surveill
ance system's ability to ascertain cases in the absence of a standard
for the true number of cases; Design: Link records of the same firearm
-related death captured by the surveillance system's multiple data sou
rces, comparing the rate of false positives and false negatives, and a
ssessing errors in linkage variables. Setting: Maryland, 1991-1994. Pa
rticipants: All deaths occurring in the state of Maryland as a result
of a firearm-related injury. Main Outcome Measures: Sensitivity and po
sitive-predictive value. Results: The system is extremely sensitive, d
etecting 99.61% of cases, and it has a very high positive predictive v
alue, with 99.87% of the cases identified from medical examiner's offi
ce data being confirmed as actual cases. Conclusions: Maryland's datab
ase of information from the medical examiner's office is highly accura
te far ascertaining firearm-related deaths that occur in the state. A
unique identifier common across data sources would ease record linkage
efforts, and improve the system's ability to monitor firearm-related
deaths.