Which sequence correctly describes the Plan-Do-Study-Act cycle in quality improvement?

• A. Do the change, Plan results, Study action, Act
• B. Plan, Act, Do, Study
• C. Plan a change, Do implement on a small scale, Study results, Act to implement or adjust and spread
• D. Plan a change, Study results, Do the change, Act

Answer: (C)

The sequence tested here focuses on designing a change, testing it on a small scale, learning from the results, and then deciding what comes next. In quality improvement, you plan a change with expected outcomes in mind, implement it on a limited, controlled scope, study the data and what happened, and then act by either adopting the change broadly, adjusting it, or abandoning it and starting another cycle. The emphasis on small-scale testing and learning before wide implementation is what makes this order correct.

Other sequences misplace steps—for example, trying the change before planning, or evaluating results before actually doing the change, or moving to act before you’ve studied the outcomes—which breaks the logical flow of testing and learning that the PDSA cycle uses.