Improve phase: improvement and waste-elimination tools
Improve turns verified causes into changes that work in practice. The exam asks you to choose a suitable tool for a situation, to know how solutions are generated and selected with discipline, and to recognise Lean techniques by name and purpose.
Generate, select, test
- Brainstorming: silent generation first, no criticism, build on others, then cluster the output.
- Benchmarking and SCAMPER prompts keep the option set wider than one person's preferred fix.
- Selection: impact/effort matrix for speed, Pugh matrix against a datum, FMEA (RPN = Severity × Occurrence × Detection) to expose risk the change creates.
- Pilot: small-scale, time-boxed, measured against the same operational definitions and the Measure baseline.
Lean elimination tools
- 5S: Sort, Set in order, Shine, Standardize, Sustain - workplace discipline that makes other waste visible.
- Poka-yoke: mistake-proofing by prevention (impossible to do wrong) or detection (immediately obvious).
- SMED: separate internal from external setup to cut changeover time.
- Kanban and pull: replenishment triggered by consumption, not forecast.
- Standard work and line balancing: agreed task sequence matched to takt time.
- Cellular layout: equipment grouped by product family to cut transport and waiting.
Worked example
An FMEA scores mislabelled totes at RPN 168 (S=7, O=6, D=4) and a scanner that cannot read damaged labels at RPN 126 (S=9, O=2, D=7). Ranking by RPN alone favours 168, but severity 9 signals a safety or compliance risk and detection 7 is weak. Reasoning: a high-severity failure is addressed first regardless of the RPN total; RPN is a prioritisation aid, not a decision rule.
Traps that cost marks
- Selecting the first idea that fits the cause.
- Buying a capital solution when a poka-yoke or layout change is cheaper, faster and more robust.
- Piloting without holding the measurement system and definitions constant.
- Treating 5S as a cleaning campaign rather than a workplace standard.
- Ignoring waste or defects shifted downstream by the change.