The management of police patrol operations is a complex endeavor. On the one hand police are the principal public agency responsible for implementing crime control policy, while on the other hand they respond to the multitude of other problems which befall urban residents. Police are trained in the use of deadly force and other instruments of violence, but they are most commonly confronted with mundane, non-threatening problems. One of the dilemmas facing police administrators is how to balance the critical and non-critical demands for police service. Most would place threats to life and limb, whether the result of crime or accidental misfortune, in the former category, while relegating what turns out to be the majority of police duties to the non-critical category. Included among this latter group are verbal disputes among neighbors or relatives (although either of these may erupt into violent attacks), uncivil behavior in the form of homeless derelicts or teenagers occupying their street corner turf, and such criminal events as burglaries discovered by householders returning from an extended vacation. The variety of events which precipitate the mobilization of police includes some incidents which clearly require a rapid police response, others which may be resolved as well, if not better, without police intervention, and, what is probably the largest group, those incidents in which it is unclear whether action by the police is either necessary or desirable. Given this task environment, it is safe to say only that law enforcement agencies must be flexible enough to expect the proverbial unexpected. Not only are police unsure what their next encounter with clients on the street will produce, they are also uncertain about when they will be mobilized and where they will be sent. The vast *majority of mobilizations are reactive, in which police respond to calls for assistance from urban residents.' A relatively small number of police encounters with citizens are the result of officer-initiated activity. Opera-