Current research and practice in production planning and control is dominated by hierarchical, material requirements planning- based methods. Despite advances in computer technology, little real advance has occurred in the performance of U.S. manufacturing logistics management. The objective of this project is to assess the merits of a major re-direction in the design of manufacturing planning systems which exploits computer technology. This project will test the relative performance of two fundamentally different classes of manufacturing planning systems: Those that make no use of sequencing and scheduling information in the order release planning process, and those which use such information to determine order releases. A computer simulation model of a general multi-item, multi-state manufacturing system will be used to conduct controlled experiments for evaluating the relative performance of the two approaches as measured by a number of different criteria over a wide range of operating environments.