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}}

The '''Seven Basic Tools of Quality''' is a designation given to a fixed set of graphical techniques identified as being most helpful in [[troubleshooting]] issues related to [[Quality (business)|quality]].<ref>{{cite book | last = Montgomery | first = Douglas | title = Introduction to Statistical Quality Control | publisher = [[John Wiley & Sons]], Inc. | date = 2005 | ___location = [[Hoboken, New Jersey]] | pages = 148 | url = http://www.eas.asu.edu/~masmlab/montgomery/ | isbn = 978-0-471-65631-9 | oclc = 56729567 | deadurl = yes | archiveurl = https://web.archive.org/web/20080620095346/http://www.eas.asu.edu/~masmlab/montgomery/ | archivedate = 2008-06-20 | df = }}</ref> 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.<ref>{{Citation | last = Ishikawa | first = Kaoru | authorlink = Kaoru Ishikawa | title = What Is Total Quality Control? The Japanese Way | edition = 1 | year = 1985 | publisher = [[Prentice-Hall]] | ___location = [[Englewood Cliffs, New Jersey]] | isbn = 978-0-13-952433-2 | oclc = 11467749 | page = 198 | quote = From my past experience as much as ninetey-five percent of all problems within a company can be solved by means of these tools.}}</ref>

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

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

{{Gallery

The seven tools are:<ref>{{cite web | url = http://www.asq.org/learn-about-quality/seven-basic-quality-tools/overview/overview.html | author = Nancy R. Tague | title = Seven Basic Quality Tools | year = 2004 | work = The Quality Toolbox | publisher = [[American Society for Quality]] | ___location = [[Milwaukee, Wisconsin]] | page = 15 | accessdate = 2010-02-05}}</ref><ref>{{Citation | last = Ishikawa | first = Kaoru | authorlink = Kaoru Ishikawa | title = What Is Total Quality Control? The Japanese Way | edition = 1 | year = 1985 | publisher = [[Prentice-Hall]] | ___location = [[Englewood Cliffs, New Jersey]] | isbn = 978-0-13-952433-2 | oclc = 11467749 | page = 198 | quote = 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><ref>{{Citation | last = Imai | first = Masaaki | authorlink = Masaaki Imai | title = Kaizen (Ky'zen), the Key to Japan's Competitive Success | edition = 1 | year = 1986 | publisher = [[Random House]] | ___location = [[New York City|New York]] | isbn = 9780394551869 | oclc = 13010323 | pages = 239–240 | quote = The seven statistical tools used for such analytical problem-solving are: 1. Pareto diagrams [...] 2. Cause-and-effect diagrams [...] 3. Histograms [...] 4. Control charts [...] 5. Scatter diagrams [...] 6. Graphs [...] 7. Checksheets.}}</ref>

| title = Examples

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

| align = right

*[[Check sheet]]

| perrow = 2

*[[Control chart]]

| height = 135

*[[Histogram]]

| width = 135

*[[Pareto chart]]

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

*[[Scatter plot|Scatter diagram]]

| alt1=

*[[Stratified sampling|Stratification]] (alternately, [[flow chart]] or [[run chart]])

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

| File:Check sheet for motor assembly.svg

| alt2=

| Check sheet

| File:C control chart.svg

| alt3=

| Control chart

| File:Histogram of arrivals per minute.svg

| alt4=

| Histogram

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

| alt5=

| [[Pareto chart]]

| File:Scatter diagram for quality characteristic XXX.svg

| alt6=

| Scatter diagram

| File:LampFlowchart.svg

| alt7=

| Flow chart

| File:SimpleRunChart.jpg

| alt8=

| Run chart

}}

The '''seven basic tools of quality''' are a fixed set of visual exercises 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."}}

The designation arose in [[postwar Japan]], inspired by the [[Benkei#Seven Famous Weapons|seven famous weapons]] of [[Saitō Musashibō Benkei|Benkei]].<ref>{{Citation | last = Ishikawa | first = Kaoru | authorlink = Kaoru Ishikawa | title = Introduction to Quality Control | edition = 1 | year = 1990 | publisher = 3A Corp | ___location = [[Tokyo]] | isbn = 978-4-906224-61-6 | oclc = 23372992 | page = 98 | quote = 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.}}</ref> 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 | url = http://www.improvementandinnovation.com/features/article/seven-basic-tools-quality/ | title = The seven basic tools of quality | date = 2007-11-30 | website= Improvement and Innovation.com | ___location = [[London]] | accessdate = 2013-05-18 | quote = Ishikawa had a desire to 'democratise quality': that is to say, he wanted to make quality control comprehensible to all workers, and inspired by Deming’s lectures, he formalised the Seven Basic Tools of Quality Control.}}</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 the vast majority of their workers and scaled back training to focus primarily on simpler methods which suffice for most quality-related issues.<ref>{{Citation | last = Ishikawa | first = Kaoru | authorlink = Kaoru Ishikawa | title = What Is Total Quality Control? The Japanese Way | edition = 1 | year = 1985 | publisher = [[Prentice-Hall]] | ___location = [[Englewood Cliffs, New Jersey]] | isbn = 978-0-13-952433-2 | oclc = 11467749 | page = 18 | quote = 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.}}</ref>

==Overview==

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]].<ref>{{Citation | last = Ishikawa | first = Kaoru | authorlink = Kaoru Ishikawa | title = What Is Total Quality Control? The Japanese Way | edition = 1 | year = 1985 | publisher = [[Prentice-Hall]] | ___location = [[Englewood Cliffs, New Jersey]] | isbn = 978-0-13-952433-2 | oclc = 11467749 | pages = 198–9 | quote = I divide statistical methods into the following three categories according to their level of difficulty. 1. Elementary Statistical Method (the so-called Seven Tools) [...] 2. Intermediate Statistical Method [...] 3. Advanced Statistical Method (using computers concurrently)}}</ref>

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]]

#[[Histogram]]

#[[Pareto chart]]

#[[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 [[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.<ref>{{cite book|title=A Guide to the Project Management Body of Knowledge|date=2013|publisher=Project Management Institute|___location=Newtown Square, PA|isbn=978-1-935589-67-9|pages=236–238}}</ref>

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)".}}

<gallery caption="Examples" perrow="4">

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

File:Check sheet for motor assembly.svg|Check sheet

File:C control chart.svg|Control chart

File:Histogram of arrivals per minute.svg|Histogram

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

File:Scatter diagram for quality characteristic XXX.svg|Scatter diagram

File:LampFlowchart.svg|Flow chart

File:SimpleRunChart.jpg|Run Chart

</gallery>

==See also==

*[[A3 problem solving]]

*[[Eight Disciplines Problem Solving]]

*[[Seven Management and Planning Tools]]

==References==

===Footnotes===

{{reflist}}

{{reflist|22em}}

===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

|author-link=Masaaki Imai

|year=1986

|title=Kaizen (Ky'zen): The Key to Japan's Competitive Success

|url=https://archive.org/details/kaizenkyzenkey00imai

|url-access=registration

|edition=1st

|___location=New York

|publisher=Random House

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

}}

* {{cite book

|last=Ishikawa

|first=Kaoru

|author-link=Kaoru Ishikawa

|year=1985

|title=What Is Total Quality Control? The Japanese Way

|translator-last=Lu

|translator-first=David J.

|edition=1st

|___location=Englewood Cliffs, New Jersey

|publisher=Prentice-Hall

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

|url-access=registration

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

}}

* {{cite book

|last=Ishikawa

|first=Kaoru

|author-link=Kaoru Ishikawa

|author-mask={{long dash}}

|year=1990

|title=Introduction to Quality Control

|edition=1st

|___location=Tokyo

|publisher=3A Corp

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

}}

* {{cite book

|last=Montgomery

|first=Douglas

|year=2005

|title=Introduction to Statistical Quality Control

|___location=Hoboken, New Jersey

|publisher=John Wiley & Sons

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

}}

* {{cite book

|author=Project Management Institute

|author-link=Project Management Institute

|year=2013

|title=A Guide to the Project Management Body of Knowledge

|edition=5th

|___location=Newtown Square, Pennsylvania

|publisher=Project Management Institute

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

}}

* {{cite book

|last=Tague

|first=Nancy R.

|year=2005

|title=The Quality Toolbox

|edition=2nd

|___location=Milwaukee, Wisconsin

|publisher=ASQ Quality Press

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

|url-access=registration

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

}}

{{refend}}

{{Quality Tools}}

{{Authority control}}

[[Category:Quality control tools]]