Matching heuristic scheduling rules for job shops to the business sales level

A job-shop simulation experiment is used to demonstrate the need to switch scheduling dispatch rules as business sales levels change. Given the objective of minimizing average lateness of customer orders, the simulations demonstrate the superiority of different rules as the shop load moves toward or away from shop capacity, which is assumed fixed in the short run. The study uses an 'exchange ratio' of the SPT (shortest processing time) and MS (minimum slack) rules for different levels of sales to gain the advantages of these simple, effective rules. Implementation of the suggested approach would be relatively simple.