Assessment of MRP:

The advantages related with MRP over more conventional inventory-planning approaches such as fixed order quantities and order points have been demonstrated in upcoming section. These include improved customer service, reduced inventory levels, and increased operating efficiency of production departments. The characteristics of production systems that support the successful implementation of MRP are :

• An efficient computer system           
• Accurate computerized bill of material along inventory status files for all end items and materials
• A production system that manufacture discrete products processed through several production steps built up of raw materials, parts, subassemblies, and assemblies.
• Production process with long processing times.
• comparatively reliable lead time
• The master schedule.
• Top management commitment along with its support

MRP has not been and shall not be applied to all of production systems. In some of Production Operations Management (POM) applications, MRP is either unnecessary or economically unjustifiable. The frequency of MRP usage is, however, definitely on a dramatic upward trend. As we gain more experience with MRP, we realize that it is not a panacea. It doesn't solve our entire inventory planning problems. Basically, MRP is a POM computerized information system. While computer systems are ineffective, inventory status and bills of material files are inaccurate, master production schedules are undependable, and when the remainder of the organization is otherwise mismanaged, MRP shall not be of much help. It shall generate greater volumes of inaccurate and unused information than previously thought possible. MRP is best applied while production systems are basically well managed and a more comprehensive production and inventory planning system is required.

However, for effective MRP, lead times should be reliable. Also, the MPS must be frozen for a time before actual production to the MPS is begun, meaning that what is to be generated, the MPS, should be known with certainty and the timing and quantity of raw material receipts must be dependable. While lot sizes of raw materials are large and variability in demand is small, the conventional economic lot size and order point inventory planning systems tend to work quite well because their supposition of uniform demand apply. MRP therefore offers more improvement in inventory planning when lot sizes are small and demand variability is large.