Abstract
This thesis concerns the use of simulation for investigating and describing the criminal detection activity of detective police constables engaged in ordinary C. I. D. duties in British urban police forces. Two simulation approaches are described: (1) a gaming simulation (SIMPOL), which was used to study the performance of a C. I. D. by using real policemen to operate a simulated C. I. D. This study was used to provide empirical data on the activity planning and directing involved in detective work and decision rules governing this were extracted. (2) These rules were embedded in a formal model (SIMDET) of investigation work and a computer simulation of the decision processes used by a detective to organise and plan his activities was produced. SIMDET - produces a protocol of the activity of a detective when confronted with a series of crimes to investigate and specifies the investiagtion activities he carries out, how long he spends on each, the outcomes his activities produce and his plans on each investigation. The model produces a continuous record of his activity including him going off-duty and doing activities (e. g. report writing) other than crime investigation. The model has been programmed in extended FORTRAN IV and consists of approximately 2,500 statements and 35 sub-programs. It has been run on C. D. C. 7600 and I. C. L. 1903 A computers. The conceptual basis of SIMDET is discussed and the notion of an executive control system is introduced Which is seen as a system that has the prime goal of serving a set of other goals. The computer model represents the decision processes of an executive control system serving the goals of the detective role. The thesis presents the first detailed model of detective decision processes and makes a general contribution to understanding human action.