This proposal is for a project to estimate the incidence of significant medically-treated work-related injuries for the employed population of one community. Athens County, Ohio, for the five-year period 1982-86. Two independent data sources relating to such injuries are available for this community: emergency room visits for occupation injuries, coded and entered on computer as part of the National Electronic Injury Surveillance System (NEISS); and claims for lost-time injuries filed with the Ohio Bureau or worker's Compensation and made available by the Division of Safety and Hygiene of the Ohio industrial Commission (OIC). These two datasets will be merged, so that injured persons represented in both datasets will be counted only once. Epidemiologic patterns of work-related injuries as ascertained from NEISS alone will be compared to those ascertained from the OIC system alone; and each will be compared to patterns as ascertained from the two datasets merged together. Preliminary work suggests that the degree of overlap between the two datasets is small: approximately 5 to 10% of persons in the combined datasets are in both datasets. In addition, the number of injuries resulting in either an emergency room visit or a lost-time Worker's Compensation claim, or both, will be compared to the number expected based on estimates by the United States Bureau of Labor Statistics (BLS), which uses a system based on the Form 200 of the Occupational Safety and Health Administration (OSHA). The results of the project will be useful in assessing the completeness of and biases in analyses of workplace injuries based on only Worker's Compensation or only emergency-room data, and will provide some indirect evidence about the degree of completeness of the BLS system for estimating rates of injuries.