Statistical Process Control through the use of control charts and Nelson’s Rules

Achieving compliance under Good Laboratory Practices (GLP) may pose challenges. However, establishing a monitoring system for assessing the performance of methods and instruments can alleviate these difficulties. Statistical tools can effectively oversee critical variables during procedure execution and instrument performance. Employing Nelson's rules allows for the evaluation of data, determining whether it aligns with expected performance or deviates statistically from acceptable standards. Importantly, this assessment can occur even when the overall procedure remains in compliance, enabling the continued use of the procedure as intended.

Most laboratories monitor the results of a procedure by tracking the results of running standards and using a control chart. This, however, is a very simplistic and limited way of assessing performance. When the procedure fails, the laboratory is not in compliance. This is a very dire situation.

Many of the activities in the procedure follow Gaussian statistics. This means that choosing a metric for key activities or parts of the procedure can show the causes of the overall problem. Using the 3-sigma occurrence as the only evaluation is also a poor approach. Statistically, there are many other tests for good Gaussian behavior. The set of Nelson’s rules gives these. This allows for monitoring symptoms and catching problems as they develop.

• The statistics of data
• Control charts and their underlying statistics
• Nelson’s Rules
• How the data shows an indication of a problem
• Maintaining the records
• Planning adjustments
• How to choose important variables and set up a control chart to monitor
• Review of the relevant statistics

Statistical Process Control through control charts and Nelson's Rules play a crucial role in modern quality management. By harnessing statistical methods and visual representations, organizations can not only monitor the stability of their processes but also identify and address deviations promptly. This proactive approach fosters a culture of continuous improvement, ensuring that products and services consistently meet or exceed customer expectations.