Continuous Improvement and Problem Solving
What the exam tests
This domain tests structured problem solving: defining a problem with facts, finding root causes, selecting countermeasures, and locking in gains through standard work. Expect PDCA, A3 thinking, 5 Whys, Pareto, fishbone, and run charts.
Core rules and concepts
- State the problem as a gap between current and target condition, with who, what, where, when, and magnitude. Avoid embedding a cause or solution in the statement.
- PDCA is the umbrella: plan the gap and cause, do the countermeasure on a small scale, check results against the target, act by standardizing or adjusting.
- DMAIC is a data-heavy variant for improvement projects: define, measure, analyze, improve, control.
- Use Pareto to focus, fishbone to generate cause categories, and 5 Whys to drill into a chosen branch. Verify causes with evidence; a plausible story is not a root cause.
- An A3 tells the story on one page: background, current condition, target, analysis, countermeasures, plan, follow-up.
Worked example
On-time delivery is 85% against a 98% target. A Pareto of late orders shows 70% involve one purchased part. Five Whys: the part is short (why?), reorder point is too low (why?), demand rose 30% after a new customer (why?), no one reviewed the reorder point (why?), the planning standard has no trigger for demand changes. The reasoning: the root cause is a missing review trigger, not the supplier's unreliability. Countermeasures: recalculate the reorder point, add a monthly demand-review step, and track part availability on a run chart. Verify the 98% target over four weeks before closing.
Traps that cost marks
Jumping to a solution; stopping at operator error; using 5 Whys as a linear ritual when causes interact; confusing common-cause variation with a special cause; and treating the A3 as a form to fill rather than a thinking process.