Quality management explained: definitions, Garvin's eight dimensions, planning, control, assurance and improvement, TQM tools, PDCA, and a worked cost of quality example.
Updated 12 min read
Quality is the degree to which a product or service meets its specifications and satisfies customer needs; in Joseph Juran's short phrase, it is fitness for use. Quality management is the coordinated set of activities (planning, control, assurance and improvement) that makes sure an organisation delivers that quality consistently and economically.
A customer buying a pen expects it to write smoothly, not leak, last a reasonable time and look acceptable. A company making lakhs of pens has to make sure that nearly every one meets that expectation, and the system it uses to do so is quality management. Poor quality leads to complaints, returns, scrap and lost sales; good quality builds trust, reduces waste and becomes a competitive advantage.
Productivity improves because more output is good first time
Sales and employee morale suffer
Long-term profit and pride in work improve
Legal and warranty liabilities grow
The firm can compete on quality, not only on price
The objective of quality management is to produce goods and services that meet specifications and satisfy customers at the lowest total cost. That means proper performance, consistency, reliability, few defects and cost control together. The practical aim is consistent quality delivered efficiently, not perfection at any price.
User-based: quality is what the customer says it is; fitness for use.
Manufacturing-based: quality is conformance to requirements (Philip Crosby's phrase), that is, meeting the specification.
Product-based: quality is a measurable attribute, such as the thread count of a shirt.
Value-based: quality is performance at an acceptable price.
A product can meet every internal specification and still disappoint customers. A restaurant may serve food quickly, but if taste and hygiene are poor, customers call it low quality. Quality management must therefore look both at specifications and at customer expectations.
For products, quality covers performance, size, durability, appearance, design and freedom from defects: a mobile phone should work properly, look good and not fail often. For services, it covers speed, accuracy, courtesy, reliability, responsiveness and the overall experience: in a hospital, correct treatment, cleanliness, quick response and proper patient care.
David Garvin of Harvard Business School proposed that product quality has eight dimensions. A product can be strong on some and weak on others.
Dimension
Meaning
Example
Performance
How well the product does its main job
A fan moves enough air
Features
Extra characteristics, the "bells and whistles"
Several wash modes on a washing machine
Reliability
Probability of failure-free operation over a stated period
A refrigerator that runs for years without breakdown
Conformance
Degree to which it matches design specifications and standards
A bolt within its diameter tolerance
Durability
How long it lasts before it wears out
Shoes that last three years
Serviceability
Ease, speed and courtesy of repair
A local service centre fixes a scooter in a day
Aesthetics
Look, feel, sound, colour, packaging
An attractive, well-finished phone
Perceived quality
Quality inferred from brand, reputation and advertising
Trusting a well-known brand of medicine
Reliability matters most for medical equipment, vehicles, electronics and machinery, where failure is costly or dangerous. Aesthetics shapes first impressions and acceptance. Quality is therefore both functional and experiential.
For services, the widely taught SERVQUAL model uses five dimensions: tangibles (facilities and appearance), reliability (doing what was promised, accurately), responsiveness (willingness to help promptly), assurance (knowledge and courtesy that inspire trust) and empathy (individual care and attention).
Quality management is a complete system, not just inspection. Juran described it as a trilogy of planning, control and improvement; assurance is usually added as a fourth element.
Checking whether actual output meets the required standard and correcting deviations. It includes inspection, testing and statistical process control, and maintains the desired level of quality.
Planned and systematic activities that give confidence that the system is capable of producing quality consistently, such as documented procedures, audits, supplier approval and certification. Quality control finds problems in the output; quality assurance prevents them in the process.
Continuously raising performance by removing the causes of defects, using tools such as PDCA, Six Sigma projects and employee suggestion schemes.
Basis
Inspection
Quality control
Quality management
Focus
Sorting good from bad items
Keeping the process to standard
The whole system, including prevention and improvement
Inspection: finished goods are checked and defective ones removed.
Statistical quality control: Walter Shewhart's control charts in the 1920s and 1930s monitored process variation, and acceptance sampling reduced inspection cost.
Quality assurance: the focus moved to preventing defects through systems, procedures and design.
Total quality management (TQM): quality becomes a company-wide strategy built on customer focus, continuous improvement and employee involvement, strongly influenced by W. Edwards Deming, Joseph Juran and Japanese practice after the Second World War.
Deming popularised the Plan–Do–Check–Act cycle, which Shewhart had originated. The team plans a change after finding the cause of a problem, tries it on a small scale, checks the results against the target and then acts, either standardising the change or starting the cycle again.
The PDCA cycle turns continuously; each turn locks in a gain before the next begins.
Check sheet: a simple form for tallying defects by type or location.
Histogram: shows the distribution of a measurement.
Pareto chart: ranks causes so the vital few that cause most defects are tackled first.
Cause-and-effect (Ishikawa or fishbone) diagram: lists possible causes under headings such as man, machine, method, material, measurement and environment.
Scatter diagram: shows the relationship between two variables.
Flow chart: maps the steps of a process.
Control chart: tracks a process over time against statistical limits; it is covered in the article on statistical quality control.
Six Sigma: a data-driven method that aims for no more than 3.4 defects per million opportunities, using the DMAIC steps (Define, Measure, Analyse, Improve, Control).
ISO 9001: an international standard for quality management systems; certification shows that documented, audited processes are in place.
Poka-yoke (mistake-proofing): simple devices that make an error impossible or immediately visible.
Benchmarking and quality function deployment (QFD), which translates customer needs into design requirements.
Quality is not free to achieve. The cost of quality (COQ) is the total cost of preventing, detecting and correcting defects. It is usually divided into four categories.
Costs of activities that stop defects from occurring: training, quality planning, process improvement, preventive maintenance, product design reviews and supplier development.
Costs of defects found after delivery: returns, warranty claims, replacements, complaint handling, product recalls, liability and lost goodwill.
Prevention and appraisal are the costs of conformance; internal and external failure are the costs of non-conformance. The central lesson is that prevention is usually cheaper than correction: each rupee spent on prevention can save several rupees of failure cost, and external failures are the most expensive because they also damage reputation.
Suppose a plastic bottle maker (hypothetical figures) has annual sales of ₹4 crore (₹400 lakh). In Year 1 it relies on inspection and records the following quality costs. In Year 2 it doubles its spending on prevention (operator training, better mould maintenance and supplier checks).
Category
Year 1 (₹ lakh)
Year 2 (₹ lakh)
Change (₹ lakh)
Prevention
2.0
4.0
+2.0
Appraisal
3.0
2.5
−0.5
Internal failure
6.0
3.0
−3.0
External failure
9.0
3.5
−5.5
Total COQ
20.0
13.0
−7.0
Step 1: total cost of quality.
Year 1=2+3+6+9=20 lakhYear 2=4+2.5+3+3.5=13 lakh
Step 2: COQ as a percentage of sales.
Year 1=40020×100=5.0%Year 2=40013×100=3.25%
Step 3: failure costs as a share of COQ.
Year 1=206+9×100=75%Year 2=133+3.5×100=50%
Step 4: return on the extra prevention spending. An extra ₹2 lakh on prevention produced a net saving of ₹7 lakh in total quality cost. Failure costs alone fell by 15−6.5=8.5 lakh, so each extra rupee on prevention cut failure costs by
28.5=4.25 rupees
This is the "prevention is cheaper than correction" principle in numbers.
Spending more on prevention shrinks failure costs and cuts total cost of quality from 5 per cent to 3.25 per cent of sales.
Quality management is at the core of operations, because operations produces the goods and services. When quality is out of control, material and machine time are wasted, schedules are disrupted and customers are let down. Quality links closely with production efficiency, inventory (defects need safety stock), maintenance (worn equipment makes defects), the supply chain (bad inputs make bad outputs) and customer service.
Good quality also raises productivity. Fewer defects mean less rework, fewer delays, less inspection effort and less wasted material and labour, so the same resources yield more acceptable output. This is why the belief that high quality always means high cost is only partly true: better prevention often lowers total cost, as the example shows.
Raw material checks, process control, dimensional accuracy, final inspection, product reliability and defect reduction. A furniture factory, for instance, controls wood quality, cutting accuracy, finish, joint strength and final appearance.
What is the difference between quality control and quality assurance?#
Quality control checks the output and corrects defects that have occurred, so it is detection-oriented. Quality assurance builds procedures, audits and systems so that defects are prevented, so it is prevention-oriented.
What are Garvin's eight dimensions of quality?#
Performance, features, reliability, conformance, durability, serviceability, aesthetics and perceived quality.
What are the components of the cost of quality?#
Prevention costs (such as training), appraisal costs (such as inspection), internal failure costs (such as scrap and rework) and external failure costs (such as warranty claims and returns).
Why is external failure cost considered the worst?#
Because the defect has reached the customer. Besides repair or replacement, the firm pays in complaints, lost goodwill and lost future sales, which are hard to measure and recover.
Not necessarily. Higher design grade can cost more, but better conformance through prevention usually reduces scrap, rework and returns, so total cost often falls. In the example, total quality cost fell from ₹20 lakh to ₹13 lakh.
How is inspection different from quality management?#
Inspection only sorts good items from bad after or during production. Quality management covers planning, prevention, control and improvement across the whole organisation, and inspection is just one small part of it.
