Quality Improvement Papers
Using the SAS® System to Construct and Operate Control
Charts with Randomized Control Limits
Peter Wludyka, SUGI Proceedings, 2003.
Abstract
Attribute control charts (e.g., charts for counts and proportions) have discrete jumps in the quantities plotted on the charts, which means that the chart designer has only a discrete set of unique control limits to choose from when designing a chart. These charts have a small set of in-control Average Run Lengths (ARLs) from which to determine the appropriate control scheme. In a chart with randomized control limits the operational control limit in an epoch is determined by a random choice from among a set of control limits. The resulting control chart will then have a predetermined in-control ARL. These charts can be thought of as ones with optimal ARL properties. SAS® programs for designing and operating these charts will be provided.
