01 · 1920s–1980s
Statistical process-control foundations
Control charts, variation analysis and industrial quality methods established quantitative approaches to process performance.
ASSURANCE DNA · SIX SIGMA METHODS
A structured Six Sigma improvement method: define, measure, analyse, improve and control, supported by appropriate quantitative tools.
Which measured process problem is being solved, and can the improvement survive control?
DMAIC is for improving an existing process with a measurable problem. It should not be forced onto invention, vague transformation or a process with unusable data. Source-bounded interpretation: no certification, protected text reproduction or award prediction.
LIVING EXPERIMENT · MICROSCOPE
The visitor changes magnification from claim to process step to variation. Unsupported averages blur; defined measures and controls sharpen the image.
ORIGIN × EVOLUTION × CURRENT PRACTICE
High-volume or repeatable manufacturing, transactional, service, health, logistics and public processes where variation and defects can be measured.
01 · 1920s–1980s
Control charts, variation analysis and industrial quality methods established quantitative approaches to process performance.
02 · 1980s–1990s
Motorola and later adopters popularised structured, project-based reduction of defects and variation.
03 · 2011
Part 1 described DMAIC and project roles; Part 2 addressed supporting tools and techniques.
04 · 2021–2026
ISO records the 2011 parts as confirmed, retaining applicability to manufacturing, services and transactional processes.
DMAIC is inappropriate where there is no stable process, measurable problem or sufficient data. Statistical language must never camouflage weak evidence.
OFFICIAL SOURCE FRESHNESS MONITOR
Monthly official-source reachability and change review.
The check records source reachability and a content fingerprint. It does not silently change the page or claim that an edition changed.
PUBLICLY DESCRIBABLE ANATOMY
These are navigational interpretations, not substitute clauses. Use the official publication for normative wording.
Define the buyer-relevant problem, customer, process boundary, objective and project authority.
Establish operational definitions, measurement validity and a reproducible baseline.
Analyse variation and causes using evidence appropriate to the data and process.
Design and test changes on a controlled scale before embedding them in the offer.
Define control, ownership, limits and response so performance does not drift.
Govern project roles, phase reviews, decisions and benefit validation.
Select tools because they answer a question, not because they look sophisticated.
BEFORE × INTERVENTION × AFTER
A fictional shared-service bid proposes to reduce invoice exceptions from an unverified “18%” baseline.
Fictional analysis design; the numbers are teaching inputs, not claimed savings.
Four teams define an exception differently; samples exclude rejected invoices and the proposed automation precedes cause analysis.
The team standardises the definition, validates measurement, stratifies causes, tests two changes and creates response limits.
The commercial model uses a reproducible baseline and only includes the change whose controlled pilot evidence survives review.
PROPORTIONATE IMPLEMENTATION
DMAIC is for improving an existing process with a measurable problem. It should not be forced onto invention, vague transformation or a process with unusable data.
Charter, baseline, tested change, control rule
Data-quality test, causal analysis, approval
Project portfolio, control performance, lessons
SOURCE TRAIL · REVIEWED 26 JUL 2026
Publication status can change. Exact conformity questions belong with the current licensed publication and competent assurance.