Critical Ratio Scheduling with Queue Waiting Time Information: An Experimental Analysis

The Critical Ratio and Slack Time priority scheduling rules have been applied by a number of firms in computer-based scheduling systems for manufacturing operations. One question in using these rules is whether queue waiting time estimates for individual machines should be used in making scheduling decisions. Simulation experiments are reported in this paper that measure the effect of including historical queue time data in the Critical Ratio and Slack Time rules. The results suggest that such data can adversely affect shop performance, measured using criteria such as job flow times, job lateness, and inventory system costs.