Optimization and design of production and service operations has been a cornerstone of simulation applications for many years. Recently there has been increasing interest in excellence in process execution, for service processes, supply chains, and manufacturing operations. Simulation again has an important role to play, in evaluating the effectiveness of different execution monitoring schemes. The focus of analysis changes in this setting, however, from monitoring characteristics of resources, such as queue length, waiting time and utilization, to monitoring the timeliness and correctness of the progress of entities through the system, and reacting with real-time adjustments to resources and routings. This paper describes the types of simulation analysis needed, and identifies difficulties in conducting such simulation studies using current commercial software.