Keywords: schedule performance measurement, SPC, statistical process control, control charts, job shop scheduling, data transformation
Schedule performance measurement based on statistical process control charts
In a job–shop environment, achieving a schedule that is on target is difficult due to the dynamism of factors affecting the system. In this paper the Shewart's Individuals control chart is applied to a scheduling process for the purpose of measuring schedule performance. The charts are applied to monitor the deviations of actual from scheduled process times for jobs on a process machine. Data transformation operations are used to counter the negative effects of non–normal data. The proposed methodology enables a scheduler study the variations between scheduled and actual outcomes, seek ways of eliminating these variations and check if process improvements have been effective. SPC charts have not been used to measure schedule performance in a job shop setting, so this paper uniquely contributes to research within the field.