Quality is not an inspection activity — it is built into processes through good design, capable systems, and a culture of continuous improvement. This page covers the key quality management concepts, tools, standards, and thinkers that every Lean Six Sigma practitioner should know.
The Quality Pioneers
Modern quality management was shaped by a small group of visionary thinkers. Their ideas form the theoretical foundation of both Lean and Six Sigma.
Developed Statistical Process Control and the PDCA cycle. His 14 Points for Management transformed Japanese industry post-WWII and remain foundational today.
Introduced the Juran Trilogy — Quality Planning, Quality Control, and Quality Improvement. Championed the idea that most quality problems are management-controllable, not operator-controllable.
Coined the concepts of "Zero Defects" and "Do It Right First Time." His book "Quality is Free" argued that the cost of poor quality always exceeds the cost of prevention.
Developed the fishbone (Ishikawa) diagram and championed the 7 Basic Quality Tools. Pioneered quality circles and the concept of total quality control involving all employees.
Deming's Philosophy
Deming's 14 Points provide a framework for transforming business effectiveness. They remain as relevant today as when first published — and directly underpin Lean Six Sigma thinking.
Aim for long-term improvement of products and services rather than short-term profit focus.
Management must awaken to the challenge of a new economic age and refuse to accept poor quality and service.
Build quality into the product from the start — inspection is too late and unreliable as a quality tool.
Instead, minimise total cost. Move towards a single supplier for each item, building long-term relationships.
Continually improve every process in planning, production, and service to improve quality and reduce costs.
Train all employees — including managers — in their jobs. Inconsistent training leads to process variation.
The aim of supervision should be to help people, machines, and processes do a better job — not to police them.
Create an environment where people feel safe to ask questions, report problems, and suggest improvements without fear of reprisal.
Departments must work as a team to anticipate problems and solve them. Silos are a major source of process waste.
Slogans create adversarial relationships. Most causes of low quality lie with the system — not the individual.
Quotas and MBO focus on numbers, not quality and methods. Substitute leadership and continuous improvement instead.
Allow people to take pride in their work. Annual ratings and merit systems create competition and destroy teamwork.
Encourage vigorous education and continuous learning for everyone. A company's most important asset is its people.
The transformation is everyone's job. Put every person in the company to work to accomplish it.
Ishikawa's Legacy
Kaoru Ishikawa identified these seven tools as sufficient to solve the vast majority of quality problems. They are the core toolkit for any quality improvement practitioner.
Also called the Fishbone or Ishikawa diagram. Identifies and organises potential root causes of a problem across categories.
Root cause analysisMonitors process performance over time, distinguishing between common cause and special cause variation.
Process monitoringA bar chart ranking defects or causes by frequency. Based on the 80/20 principle — focus on the vital few causes.
PrioritisationDisplays the distribution of data — shape, centre, and spread. Used to assess process capability and normality.
Data distributionPlots two variables to identify the relationship (correlation) between a potential cause and an effect.
Correlation analysisA structured form for collecting and recording data in real time. Simple but powerful for defect tracking and data collection.
Data collectionSeparates data from multiple sources into meaningful groups (by machine, shift, operator) to reveal hidden patterns.
Data analysisThe Improvement Cycle
The PDCA cycle, developed by Shewhart and popularised by Deming, is the fundamental model for continuous improvement. It underpins Six Sigma's DMAIC, Lean's Kaizen events, and ISO 9001 management systems alike.
Identify the problem, analyse the current situation, set objectives, and plan the improvement. Determine what changes to make and predict expected results.
Implement the planned change on a small scale. Carry out the experiment or pilot. Collect data during execution.
Study the results. Compare actual outcomes to predicted outcomes. Did the change achieve the desired improvement?
If successful, standardise and implement fully. If not, learn from the experiment and return to the Plan stage with new knowledge.
Quality Standards
ISO standards provide internationally recognised frameworks for quality management systems. They complement Lean Six Sigma by providing the structural foundation within which improvement tools operate.
The world's most widely used quality management standard. Specifies requirements for a QMS focused on customer satisfaction, process approach, and continual improvement. Closely aligned with DMAIC and Lean principles.
Framework for organisations to manage their environmental responsibilities. Shares the Plan-Do-Check-Act structure with ISO 9001, making integrated management systems straightforward.
The international standard for occupational health and safety management systems. Helps organisations reduce workplace incidents — directly connected to Lean's focus on safe, standard work.
The quality management standard for the automotive supply chain, built on ISO 9001. Mandates use of core quality tools including FMEA, SPC, MSA, and PPAP.
Quality management systems for medical devices — a highly regulated sector where Six Sigma tools and risk management are essential compliance requirements.
International guidelines for risk management principles and processes. Provides the broader risk framework within which FMEA and other Six Sigma risk tools operate.
Reference: ISO Official Website →
Reference Materials
A comprehensive reference for all major quality tools — descriptions, when to use, and worked examples.
The professional body for quality management practitioners in the UK and internationally.
The story of how Shewhart's Statistical Process Control was developed and adopted by Deming.
Official source for all ISO standards — search, preview, and purchase any standard directly.
The American Society for Quality's extensive library of quality management reference materials.