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Defining Quality

This article explores the concept of quality and its dimensions in supply chain management. It discusses different definitions of quality, the importance of quality, and the costs associated with quality. It also highlights the contributions of quality experts such as W. Edwards Deming, Joseph Juran, and Philip B. Crosby.

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Defining Quality

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  1. Defining Quality SCM 494 – Managing for Quality Dr. Tibben-Lembke

  2. What is Quality? • Dad and son cycle across US • Dad has had electro-shock therapy, and keeps recognizing things on the trip • Not supposed to remember • Realizes needs more help • Used to be philosophy prof. • Defining “quality” drove him over the edge the first time

  3. What is Quality? Quality … you know what it is, yet you don’t know what it is. But that’s self-contradictory. But some things are better than others, that is, they have more quality. But when you try to say what the quality is, apart from the things that have it, it all goes poof! There’s nothing to talk about. ... Robert M. Pirsig, Zen and the Art of Motorcycle Maintenance, p. 163

  4. What is Quality? Obviously, some things are better than others … but what’s the “betterness”? So round and round you go, spinning mental wheels and nowhere finding anyplace to get traction. What the hell is Quality? What is it? Robert M. Pirsig, Zen and the Art of Motorcycle Maintenance, p. 164

  5. What is Quality?

  6. Some Definitions of Quality “Quality is conformance to requirements” -- Philip Crosby, “Quality is Free” 1979 The totality of features and characteristics of a product or service that bear on its ability to satisfy stated or implied needs. --ASQC

  7. What is Quality? • User-based: “In the eyes of the beholder” • Manufacturing-based: “Right the first time” • Product-based: Precise measurement

  8. Further Definitions • “Conformance to valid customer requirements” • Goalpost View: “Acceptable as long as it is within acceptable limits” p. 17 • “a predictable degree of uniformity and dependability, at low cost and suited to the market.” p.18

  9. ` Loss Function Probability of size Loss Function

  10. Total Quality Management An emphasis on Quality that encompasses the entire company • Continuous Improvement • Employee empowerment, quality circles • Benchmarking - best at similar activities, even if in different industries • Just In Time - requires quality of suppliers • TQM Tools - allow you to measure progress

  11. Quality Dimensions • Quality of Design • Quality characteristics suited to needs and wants of a market at a given cost • Continuous, never-ending improvement • Quality of Conformance • Predictable degree of uniformity and dependability • Quality of Performance • How is product performing in the marketplace?

  12. Dimensions of Quality • Performance • Aesthetics • Special features: convenience, high tech • Safety • Reliability • Durability • Perceived Quality • Service after sale

  13. Costs of Quality • Internal failure costs – before delivered to customers • External failure costs – after delivered • Appraisal costs – assessing conformance to standards • Prevention Costs – reducing potential for quality problems

  14. Importance of Quality • Lower costs (less labor, rework, scrap) • Market Share • Reputation • Product liability • International competitiveness

  15. Roots of Quality 1920’s Bell Labs: • Acceptance Sampling • Want to guarantee certain % defective, • How many do we need to sample? • Supposedly 2% defective, we test 40 and 2 are bad, are more than 2% bad?

  16. Inspection • Does not add value • Inspectors distrusted by workers • Increase quality and reduce need for inspectors • Poka-yoke - “mistake proof” • Have workers do own inspecting • Before – are inputs good? • During – process happening properly? • After – conforms to standards?

  17. Inspect all or None • k1 = Cost of inspecting one item • k2 = Cost to dismantle, repair, reassemble and test a good or service that fails because of a bad input • p = average fraction defective of incoming materials • If k1/k2 > p inspect 0% • If k1/k2 < p inspect 100% • If k1/k2 = p either 0% or 100%. If p is based on not a lot of data, use 100%

  18. W. Edwards Deming • Statistics professor, specializing in acceptance sampling • Went to Japan after WW II • Helped Japanese focus on and improve quality • System (not employees) is cause of poor quality • Fourteen Points

  19. Deming’s Paradigms • Intrinsic & extrinsic motivation • Management needs to improve and innovate processes to create results • Optimize the system toward its aim • Cooperation is better than competition

  20. Joseph Juran • Went to Japan in 1951 • Quality begins by knowing what customers want • 80% of defects are controllable • Quality Planning • Quality control • Quality improvement

  21. Philip B. Crosby • Martin Marietta, ITT, starting in 1960s • “Quality is Free” • Management must be firmly behind any quality plans • Do it right the first time

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