Seven basic tools of quality: Difference between revisions

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{{Short description|Fixed set of visual exercises for troubleshooting issues related to quality}}

{{Use British English Oxford spelling|date=October 2018}}

{{Use dmy dates|date=October 2018}}

{{Gallery

| title = Examples

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| File:Cause and effect diagram for defect XXX.svg

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| [[Ishikawa diagram|Cause-and-effect diagram]]

| File:Check sheet for motor assembly.svg

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| File:Pareto chart of titanium investment casting defects.svg

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| [[Pareto chart]]

| File:Scatter diagram for quality characteristic XXX.svg

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| Run chart

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The '''seven basic tools of quality''' is a designation given toare a fixed set of graphicalvisual techniquesexercises identified as being most helpful in [[troubleshooting]] issues related to [[quality (business)|quality]].{{sfn|Montgomery|2005|p=148}} They are called ''basic'' because they are suitable for people with little formal training in statistics and because they can be used to solve the vast majority of quality-related issues.{{sfn|Ishikawa|1985|p=198|ps=: "From my past experience as much as ninety percent of all problems within a company can be solved by means of these tools."}}

==Overview==

The seven tools are:{{sfn|Tague|2005|p=15}}<ref>{{harvnb|Ishikawa|1985|p=198|ps=: "Elementary Statistical Method (the so-called Seven Tools) 1. Pareto chart: The principle of vital few; trivial many 2. Cause and effect diagram (This is not precisely a statistical technique) 3. Stratification 4. Check sheet 5. Histogram. 6. Scatter diagram (analysis of correlation through determination of median; in some instances, use of binomial probability paper) 7. Graph and control chart (Shewhart control chart)".}}</ref>{{sfn|Imai|1986|pp=239–240|ps=: "The seven statistical tools used for such analytical problem-solving are: 1. Pareto diagrams&nbsp;... 2. Cause-and-effect diagrams&nbsp;... 3. Histograms&nbsp;... 4. Control charts&nbsp;... 5. Scatter diagrams&nbsp;... 6. Graphs&nbsp;... 7. Checksheets."}}

#[[Ishikawa diagram|Cause-and-effect]] diagram (also known as the "fishbone diagram" or Ishikawa diagram)

#[[Check sheet]]

#[[Control chart]]

#[[Stratified sampling|Stratification]] (alternatively, [[flow chart]] or [[run chart]])

#[[Pareto chart]]

#[[Histogram]]

#[[Pareto chart]]

#[[Ishikawa diagram|Cause-and-effect]] diagram (also known as the "fishbone diagram" or Ishikawa diagram)

#[[Scatter plot|Scatter diagram]]

#[[Stratified sampling|Stratification]] (alternatively, [[flow chart]] or [[run chart]])

The designation arose in [[postwar Japan]], inspired by the [[Benkei#Seven weapons|seven famous weapons]] of [[Benkei]].{{sfn|Ishikawa|1990|p=98|ps=: "They were named the Seven QC Tools after the famous seven weapons of the Japanese [[Kamakura period|Kamakura-era]] warrior-priest Benkei which enabled Benkei to triumph in battle; so too, the Seven QC Tools, if used skillfully, will enable 95% of workplace problems to be solved. In other words, intermediate and advanced statistical tools are needed in about only 5% of cases."}} It was possibly introduced by [[Kaoru Ishikawa]] who in turn was influenced by a series of lectures [[W. Edwards Deming]] had given to Japanese engineers and scientists in 1950.<ref>{{cite web |last=Moore |first=Matthew |date=30 November 2007 |title=The Seven Basic Tools of Quality |url=http://www.improvementandinnovation.com/features/article/seven-basic-tools-quality/ |website= Improvementandinnovation.com |___location=London |archive-url=https://web.archive.org/web/20121019014101/http://www.improvementandinnovation.com/features/article/seven-basic-tools-quality/ |archive-date=19 October 2012 |access-date=18 May 2013}}</ref> At that time, companies that had set about training their workforces in [[quality control|statistical quality control]] found that the complexity of the subject intimidated most of their workers and scaled back training to focus primarily on simpler methods which suffice for most quality-related issues.{{sfn|Ishikawa|1985|p=18|ps=: "It is true that statistical methods are effective, but we overemphasized their importance. As a result, people either feared or disliked quality control as something very difficult. We overeducated people by giving them sophisticated methods where, at that stage, simple methods would have sufficed."}} The [[Project Management Institute]] references the seven basic tools in ''[[A Guide to the Project Management Body of Knowledge]]'' as an example of a set of general tools useful for planning or controlling project quality.{{sfn|Project Management Institute|2013|pp=236–238}}

The seven basic tools stand in contrast to more advanced statistical methods such as [[survey sampling]], [[acceptance sampling]], [[statistical hypothesis testing]], [[design of experiments]], [[multivariate analysis]], and various methods developed in the field of [[operations research]].{{sfn|Ishikawa|1985|pp=198–199|ps=: "I divide statistical methods into the following three categories according to their level of difficulty. 1. Elementary Statistical Method (the so-called Seven Tools)&nbsp;... 2. Intermediate Statistical Method&nbsp;... 3. Advanced Statistical Method (using computers concurrently)".}}

__NOTOC__

==See also==

* {{annotated link|A3 problem solving}}

* {{annotated link|Eight disciplines problem solving}}

* {{annotated link|Seven management and planning tools}}

==References==

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===Bibliography===

{{refbegin|35em|indent=yes}}

* {{cite book |last1=Duffy |first1=Grace L. |last2=Furterer |first2=Sandra L. |title=The ASQ Certified Quality Improvement Associate Handbook |date=8 June 2020 |publisher=Quality Press |isbn=978-1-951058-13-5 |language=en |chapter=Chapter 9. Improvement Tools}}

:* {{cite book

|last=Imai

|first=Masaaki

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|publisher=Random House

|isbn=978-0-394-55186-9

|ref=harv

}}

:* {{cite book

|last=Ishikawa

|first=Kaoru

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|publisher=Prentice-Hall

|isbn=978-0-13-952433-2

|ref=harv

|url-access=registration

|url=https://archive.org/details/whatistotalquali00ishi

}}

:* {{cite book

|last=Ishikawa

|first=Kaoru

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|publisher=3A Corp

|isbn=978-4-906224-61-6

|ref=harv

}}

:* {{cite book

|last=Montgomery

|first=Douglas

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|publisher=John Wiley & Sons

|isbn=978-0-471-65631-9

|ref=harv

}}

:* {{cite book

|author=Project Management Institute

|author-link=Project Management Institute

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|publisher=Project Management Institute

|isbn=978-1-935589-67-9

|ref=harv

}}

:* {{cite book

|last=Tague

|first=Nancy R.

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|publisher=ASQ Quality Press

|isbn=978-1-62198-045-2

|ref=harv

|url-access=registration

|url=https://archive.org/details/projectmanagersc0000benz

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{{Quality Tools}}

{{Authority control}}

{{Use British English Oxford spelling|date=October 2018}}

{{Use dmy dates|date=October 2018}}

[[Category:Quality control tools]]

{{Engineering-stub}}