HKSM

A four-step continuous improvement loop linked to Dr. W. Edwards Deming and Dr. Walter A. Shewhart. It began as Plan-Do-Check-Act (PDCA), and Deming later promoted Plan-Do-Study-Act (PDSA) to stress learning and analysis rather than simple inspection. Like Scrum, it is iterative and aims at ongoing, incremental improvement.

Key Points

• PDCA/PDSA follows Plan, Do, Check or Study, then Act to refine and repeat.
• Deming favored "Study" over "Check" to emphasize analysis and learning, not just inspection.
• Both Scrum and the Deming or Shewhart cycle use short, iterative loops for continuous improvement.
• Use data and small experiments to test changes, standardize wins, and adjust when results fall short.

Example

An agile team wants fewer failed releases. Plan: set a goal to cut rollback rate from 10% to 3% and hypothesize that adding automated smoke tests will help. Do: pilot the tests on one service for two sprints. Study/Check: compare rollback rates and defect escape data before and after. Act: if results improve, roll out the tests to all services; if not, adjust the approach and start the next cycle.

PMP Example Question

Why did Deming change PDCA to PDSA in the continuous improvement cycle?

1. To emphasize analysis and learning rather than simple inspection.
2. To shorten the cycle by removing verification activities.
3. To convert the cycle into a linear, once-through process.
4. To prioritize documentation over experimentation.

Correct Answer: A — Emphasize analysis and learning

Explanation: Deming preferred "Study" because it focuses on understanding and learning from results, not just checking for conformance.