More than 1,100 sheriff's departments, county police departments, municipal police departments, and State law enforcement agencies indicated whether or not officers were required to report incidents that involved each of 18 types of force. Survey results show that the categories of force for which reporting is most likely to be mandated are those with the greatest potential for death or serious bodily harm. A majority of departments within all four types studied are systematically collecting information on the most serious types of force: use of firearms, vehicle rammings, use of batons, use of flashlights as force, use of chemical agents, use of neck restraints, use of bodily force, and dog attacks or bites. At least one-third of the agencies within all types are already collecting data on the use of impact devices other than batons and the use of twist locks or wrist locks. More sheriff's departments and municipal police departments have high levels of force monitoring than county police departments and State agencies, and the largest sheriff's departments and municipal police departments are the most likely to require officer reporting of various types of force. These data support a system that would focus on the higher levels of force, for which most departments are already collecting information systematically. This focus would be somewhat analogous to the use of "index crimes" in the Uniform Crime Reporting system. 4 tables and 40 references