A comparative analysis of the COVERT job sequencing rule using various shop performance measures

The COVERT job shop dispatching rule was tested extensively twenty years ago with impressive results, however, since then it has been included in only one comparative analysis with other sequencing rules, and, reported instances of its application have been infrequent. In this paper, the COVERT rule is examined in detail relative to its applicability, its sensitivity to various operating parameters and performance measures, and its performance compared to several other sequencing rules including truncated SPT rules, dynamic slack rules and modified duedate rules. The performance of COVERT is examined for a variety of tardiness measures. The examination is conducted within the context of a simulation model of a machine-constrained job shop with serial jobs and random routings. The results indicate that COVERT performs well as a sequencing rule and in most instances was superior to the other sequencing rules tested both directly and across varying degrees of due-date tightness.