Job Shop Scheduling: Is Manual Application of Dispatching Rules Feasible?

Many computerized production scheduling systems have been implemented in order to make use of job dispatching rules for sequencing work on facilities. Few attempts have been made to implement such rules using manual systems, and it seems to be generally accepted that the use of a "good" dispatching rule is impossible without a computer system. The experimental evidence, however, supports the view that only under very exceptional circumstances would a computerized dispatching rule be worth implementing in preference to a manual system. This paper discusses the relative merits of the more popular dispatching rules with regard to their implementation requirements and their performance characteristics. A manual sequencing system which can be implemented at very little cost is described and the conditions required for successful use are discussed.