Which step in PDCA Cycle validates improvements?

In the PDCA cycle, the "Check" phase is responsible for monitoring, measuring, analyzing, and evaluating the performance of the management system. This includes validating whether the implemented controls, processes, and subsequent improvements are functioning as intended and achieving the desired objectives. According to Clause 9 (Performance evaluation) of ISO 22301, organizations must evaluate the effectiveness of actions taken, which inherently involves validating that any improvements or corrective actions executed in the "Do" phase have successfully resolved underlying issues before they are standardized in the "Act" phase.

A. Plan: The Plan phase identifies the need for improvements and plans them, but does not validate their effectiveness.
B. Do: The Do phase executes the improvement actions but does not measure or validate their success.
D. Act: The Act phase takes corrective actions and standardizes successful changes, relying on the validation already performed during the Check phase.

1. ISO 22301:2019, Clause 9.1 (Monitoring, measurement, analysis and evaluation).

2. ISO 9001:2015, Clause 9.1.2 (Customer satisfaction and performance evaluation).

3. "Business Continuity Management Systems: Implementation and Certification to ISO 22301", Hilary Estall, BCS Learning & Development, 2012, Chapter 9.