What is the operating principle of ISO's management system standards?

• A. The Plan-Do-Check-Act cycle (PDCA).
• B. The PDCA continuous improvement cycle.
• C. The Plan-Do-Check-Act cycle (PDCA).
• D. The Deming wheel.

Answer: (C)

The operating principle is the Plan-Do-Check-Act cycle, a continuous improvement loop that ISO management system standards use to guide how an organization plans, implements, assesses, and improves its processes. Plan sets objectives, processes, resources, and risks; Do puts those plans into action; Check measures performance, audits, and compares results against the plan; Act uses findings to make improvements, adjust plans, and prevent recurrence of issues. This cycle creates an ongoing feedback loop so systems stay aligned with goals, adapt to changes, and continually enhance performance. The Deming wheel is related in concept, but ISO specifically frames it as the PDCA cycle, which is the standard terminology used.