TABLE OF CONTENTS Control charts are a family of visual process monitoring techniques grounded in the theory of mathematical statistics. Originally, control charts were developed for use as a quality control measure in the manufacturing environment; however, more recently their application has expanded to the early detection of trends and significant changes in a variety of applications. There are six steps in constructing and using control charts to aid in backlog management:
Select the characteristic (backlog) to be monitored.
Determine the frequency and range of input.
Determine the chart control band midpoint and control limits.
Construct the chart.
Collect the data, plot the data and analyze the data
Continue to use the chart.
For this case, the characteristic is backlog labor hours, which will be input weekly as the average weekly available backlog labor hours of the previous 4 weeks. Assuming that available backlog labor hours are to be maintained within a control band of 2 to 4 weeks, the midpoint obviously is 3 weeks, the upper control limit (UCL) is 4 weeks and the lower control limit (LCL) is 2 weeks. Construction of the chart is straightforward as long as you have defined what a week of backlog is in labor hours. Since the control chart is to monitor available backlog, it is appropriate to use available labor as the yardstick. From Table 7-4 in the text, 82% of paid labor is available. In the example here, six people...
