The DMAIC phases in Six Sigma

The correct answer: C. Analyze, improve, control

✅ Why this answer

Six Sigma’s five-phase DMAIC methodology:

• Define: define the improvement opportunity.
• Measure: measure the current process performance.
• Analyze: analyze to discover the root causes of defects.
• Improve: improve by addressing the roots.
• Control: control future performance against slipping back to the old way.

The team has completed define and measure, so what remains, in order, is analyze, then improve, then control.

❌ Why the other options are wrong

• Assess, implement, close (A): “assess” is a general judgment, while “analyze” takes the causes apart; the difference is fundamental.
• Plan, do, check (B): the phases of the four-step PDCA cycle, not Six Sigma.
• Document, deploy, contract (D): a jumble; from “control” to “contract”!

💡 Key concept

The method for acronym questions: write the expansion from memory before reading the options, then compare letter by letter.

The ready distinction: DMAIC (Six Sigma’s five phases for reducing variation and defects) versus PDCA/PDSA (the four-step cycle of small repeated tests) (related questions in the full bank).

In the exam: “a small test, then an adjustment” points to PDSA. “Data-driven”, “root causes” and “controls so performance does not slip back” point to DMAIC. When the stem names the phases already done, the answer is the remaining phases in their order.

🔗 Related facts and questions

• What happens in each phase: Define: state the problem, the goal and the scope. Measure: measure current performance as the baseline. Analyze: look for root causes with tools such as the fishbone diagram and the Pareto chart. Improve: test and apply the solutions that address those causes. Control: monitor performance, often with control charts, so that the improvement holds.
  Practice question: the team is now investigating why the error rate fluctuates between shifts. Which phase is it in? → Analyze.
• Six Sigma and Lean: Six Sigma reduces variation and defects in a process. Lean removes waste, meaning steps that add no value for the patient, such as waiting, transport and rework. Many organizations combine the two in one approach.
  Practice question: lab results are late because specimens are collected and moved between three buildings in batches, while the analysis itself is accurate. Which of the two approaches fits first? → Lean; the problem is waste in transport and waiting, not defects in the result.
• DMAIC and DMADV: DMAIC improves an existing process. DMADV (Define, Measure, Analyze, Design, Verify) designs a new process or service that does not exist yet.
  Practice question: a hospital is designing a telehealth consultation service it has never had. Which of the two paths fits? → DMADV.
• The Control phase makes the difference: many improvement projects succeed at first, and then performance returns to where it was. The Control phase sets a process owner, an indicator to watch and a plan for what to do when it drifts.
  Practice question: turnaround time fell for two months and then returned to where it was. Which phase was not carried out properly? → Control.
• Other acronyms to memorize letter by letter: SMART for goals (Specific, Measurable, Achievable, Relevant, Time-bound; Attainable may appear in place of Achievable, and Realistic in place of Relevant), SBAR for communication (Situation, Background, Assessment, Recommendation), and ADKAR for change management (Awareness, Desire, Knowledge, Ability, Reinforcement).