The Westgard rules are used for laboratory quality control using “runs” consisting of measurements of multiple samples (typically 2-4 samples), called multi-rule.

The rules were originally developed by James Westgard. The rules are applied to the Levey-Jennings Chart instead of the traditional Shewhart individuals control chart, which uses slightly different calculations for the control limits.

Short hand notations are used to abbreviate different decision criteria or control rules, such as 12s to indicate 1 control measurement exceeding 2s control limits.

Westgard Rules – Lean Manufacturing and Six Sigma Definitions

https://www.leansixsigmadefinition.com/glossary/westgard-rules/

The Westgard rules are used for laboratory quality control using “runs” consisting of measurements of multiple samples (typically 2-4 samples), called multi-rule. They are based on the Western Electric Rules and Nelson Rules, but are modified for multiple samples in a laboratory setting. The rules were originally developed by James Westgard. The rules are applied