This research involves the development and analysis of a model of a particular set of real world job shops. The characteristics of the process include workers flexibility and job routings which may include assembly operations. An experimental design was used which allowed statistical comparisons to be made. Various control and staffing policies were considered, with mean flow time and mean job tardiness used as performance criteria. The shortest imminent operation time rule was found to provide the best performance in all but one situation. Workforce flexibility was observed to significantly improve both performance criteria for all dispatching rules considered.