请输入您要查询的百科知识：

　

词条 Pareto principle
释义

  1. In economics

  2. In software

  3. In sports

  4. Occupational health and safety

  5. Other applications

  6. Mathematical notes

  7. Equality measures

      Gini coefficient and Hoover index    Theil index  

  8. See also

  9. References

  10. Further reading

  11. External links

{{for|the optimal allocation of resources|Pareto efficiency}}

The Pareto principle (also known as the 80/20 rule, the law of the vital few, or the principle of factor sparsity)[1][2] states that, for many events, roughly 80% of the effects come from 20% of the causes.[3] Management consultant Joseph M. Juran suggested the principle and named it after Italian economist Vilfredo Pareto, who noted the 80/20 connection while at the University of Lausanne in 1896, as published in his first work, Cours d'économie politique. Essentially, Pareto showed that approximately 80% of the land in Italy was owned by 20% of the population.

It is an axiom of business management that "80% of sales come from 20% of clients".[4] Richard Koch authored the book The 80/20 Principle, which illustrates some practical applications of the Pareto principle in business management and life.[5]

Mathematically, the 80/20 rule is roughly followed by a power law distribution (also known as a Pareto distribution) for a particular set of parameters, and many natural phenomena have been shown empirically to exhibit such a distribution.[6]

The Pareto principle is only tangentially related to Pareto efficiency. Pareto developed both concepts in the context of the distribution of income and wealth among the population.

In economics

The original observation was in connection with population and wealth. Pareto noticed that approximately 80% of Italy's land was owned by 20% of the population.[7] He then carried out surveys on a variety of other countries and found to his surprise that a similar distribution applied.

A chart that gave the inequality a very visible and comprehensible form, the so-called "champagne glass" effect,[8] was contained in the 1992 United Nations Development Program Report, which showed that distribution of global income is very uneven, with the richest 20% of the world's population controlling 82.7% of the world's income.[9]

Distribution of world GDP, 1989[10]
Quintile of populationIncome
Richest 20% 82.70%
Second 20% 11.75%
Third 20% 2.30%
Fourth 20% 1.85%
Poorest 20% 1.40%

The Pareto principle also could be seen as applying to taxation. In the US, the top 20% of earners have paid roughly 80-90% of Federal income taxes in 2000 and 2006,[11] and again in 2018.[12]

However, it is important to note that while there have been associations of such with meritocracy, the principle should not be confused with farther reaching implications. As Alessandro Pluchino at the University of Catania in Italy points out, other attributes do not necessarily correlate. Using talent as an example, he and other researchers state, “The maximum success never coincides with the maximum talent, and vice-versa.”, and that such factors are the result of chance.[13]

In software

In computer science the Pareto principle can be applied to optimization efforts.[14] For example, Microsoft noted that by fixing the top 20% of the most-reported bugs, 80% of the related errors and crashes in a given system would be eliminated.[15] Lowell Arthur expressed that "20 percent of the code has 80 percent of the errors. Find them, fix them!"[16] It was also discovered that in general the 80% of a certain piece of software can be written in 20% of the total allocated time. Conversely, the hardest 20% of the code takes 80% of the time. This factor is usually a part of COCOMO estimating for software coding.

In sports

It has been inferred the Pareto principle applies to athletic training, where roughly 20% of the exercises and habits have 80% of the impact and the trainee should not focus so much on a varied training.[17] This does not necessarily mean that having a healthy diet or going to the gym are not important, but they are not as significant as the key activities. It is also important to note this 80/20 rule has yet to be scientifically tested in controlled studies with regards to athletic training.

In baseball, the Pareto principle has been perceived in Wins Above Replacement (an attempt to combine multiple statistics to determine a player's overall importance to a team). "15% of all the players last year produced 85% of the total wins with the other 85% of the players creating 15% of the wins. The Pareto Principle holds up pretty soundly when it is applied to baseball..."[18]

Occupational health and safety

Occupational health and safety professionals use the Pareto principle to underline the importance of hazard prioritization. Assuming 20% of the hazards account for 80% of the injuries, and by categorizing hazards, safety professionals can target those 20% of the hazards that cause 80% of the injuries or accidents. Alternatively, if hazards are addressed in random order, a safety professional is more likely to fix one of the 80% of hazards that account only for some fraction of the remaining 20% of injuries.[19]

Aside from ensuring efficient accident prevention practices, the Pareto principle also ensures hazards are addressed in an economical order as the technique ensures the resources used are best used to prevent the most accidents.[20]

Other applications

In engineering control theory, such as for electromechanical energy converters, the 80/20 principle applies to optimization efforts.[14]

The law of the few can be also seen in betting, where it is said that with 20% effort you can match the accuracy of 80% of the bettors.[21]

In the systems science discipline, Joshua M. Epstein and Robert Axtell created an agent-based simulation model called Sugarscape, from a decentralized modeling approach, based on individual behavior rules defined for each agent in the economy. Wealth distribution and Pareto's 80/20 principle became emergent in their results, which suggests the principle is a collective consequence of these individual rules.[22]

The Pareto principle has many applications in quality control.[23]{{Citation needed|date=January 2008}} It is the basis for the Pareto chart, one of the key tools used in total quality control and Six Sigma techniques. The Pareto principle serves as a baseline for ABC-analysis and XYZ-analysis, widely used in logistics and procurement for the purpose of optimizing stock of goods, as well as costs of keeping and replenishing that stock.[24]

In health care in the United States, in one instance 20% of patients have been found to use 80% of health care resources.[25], [26] [27]

Some cases of super-spreading conform to the 20/80 rule,[28] where approximately 20% of infected individuals are responsible for 80% of transmissions, although super-spreading can still be said to occur when super-spreaders account for a higher or lower percentage of transmissions.[29] In epidemics with super-spreading, the majority of individuals infect relatively few secondary contacts.

The Dunedin Study has found 80% of crimes are committed by 20% of criminals.[30] This statistic has been used to support both stop-and-frisk policies and broken windows policing, as catching those criminals committing minor crimes will supposedly net many criminals wanted for (or who would normally commit) larger ones.

Many video rental shops reported in 1988 that 80% of revenue came from 20% of videotapes. A video-chain executive discussed the "Gone with the Wind syndrome", however, in which every store had to offer classics like Gone with the Wind, Casablanca, or The African Queen to appear to have a large inventory, even if customers very rarely rented them.[31]

Mathematical notes

The idea has a rule of thumb application in many places, but it is commonly misused. For example, it is a misuse to state a solution to a problem "fits the 80/20 rule" just because it fits 80% of the cases; it must also be that the solution requires only 20% of the resources that would be needed to solve all cases. Additionally, it is a misuse of the 80/20 rule to interpret a small number of categories or observations.

This is a special case of the wider phenomenon of Pareto distributions. If the Pareto index α, which is one of the parameters characterizing a Pareto distribution, is chosen as α = log45 ≈ 1.16, then one has 80% of effects coming from 20% of causes.

It follows that one also has 80% of that top 80% of effects coming from 20% of that top 20% of causes, and so on. Eighty percent of 80% is 64%; 20% of 20% is 4%, so this implies a "64/4" law; and similarly implies a "51.2/0.8" law. Similarly for the bottom 80% of causes and bottom 20% of effects, the bottom 80% of the bottom 80% only cause 20% of the remaining 20%. This is broadly in line with the world population/wealth table above, where the bottom 60% of the people own 5.5% of the wealth, approximating to a 64/4 connection.

The 64/4 correlation also implies a 32% 'fair' area between the 4% and 64%, where the lower 80% of the top 20% (16%) and upper 20% of the bottom 80% (also 16%) relates to the corresponding lower top and upper bottom of effects (32%). This is also broadly in line with the world population table above, where the second 20% control 12% of the wealth, and the bottom of the top 20% (presumably) control 16% of the wealth.

The term 80/20 is only a shorthand for the general principle at work. In individual cases, the distribution could just as well be, say, nearer to 80/20 or 70/30. There is no need for the two numbers to add up to the number 100, as they are measures of different things, (e.g., 'number of customers' vs 'amount spent'). However, each case in which they do not add up to 100%, is equivalent to one in which they do. For example, as noted above, the "64/4 law" (in which the two numbers do not add up to 100%) is equivalent to the "80/20 law" (in which they do add up to 100%). Thus, specifying two percentages independently does not lead to a broader class of distributions than what one gets by specifying the larger one and letting the smaller one be its complement relative to 100%. Thus, there is only one degree of freedom in the choice of that parameter.

Adding up to 100 leads to a nice symmetry. For example, if 80% of effects come from the top 20% of sources, then the remaining 20% of effects come from the lower 80% of sources. This is called the "joint ratio", and can be used to measure the degree of imbalance: a joint ratio of 96:4 is very imbalanced, 80:20 is significantly imbalanced (Gini index: 76%), 70:30 is moderately imbalanced (Gini index: 28%), and 55:45 is just slightly imbalanced (Gini index 14%).

The Pareto principle is an illustration of a "power law" relationship, which also occurs in phenomena such as brush fires and earthquakes.[32]

Because it is self-similar over a wide range of magnitudes, it produces outcomes completely different from Normal or Gaussian distribution phenomena. This fact explains the frequent breakdowns of sophisticated financial instruments, which are modeled on the assumption that a Gaussian relationship is appropriate to, for example, stock price movements.[33]

Equality measures

Gini coefficient and Hoover index

Using the "A : B" notation (for example, 0.8:0.2) and with A + B = 1, inequality measures like the Gini index (G) and the Hoover index (H) can be computed. In this case both are the same.

Theil index

The Theil index is an entropy measure used to quantify inequalities. The measure is 0 for 50:50 distributions and reaches 1 at a Pareto distribution of 82:18. Higher inequalities yield Theil indices above 1.[34]

See also

{{div col|colwidth=22em}}
  • 1% rule (Internet culture)
  • 10/90 gap
  • Benford's law
  • Diminishing returns
  • Elephant flow
  • Keystone species
  • Long tail
  • Mathematical economics
  • Megadiverse countries
  • Ninety-ninety rule
  • Pareto distribution
  • Pareto priority index
  • Parkinson's law
  • Price's law
  • Principle of least effort
  • Profit risk
  • Rank-size distribution
  • Sturgeon's law
  • Vitality curve
  • Wealth concentration
  • Zipf's law
  • Microtransaction whale
{{div col end}}

References

1. ^{{cite news|url=https://www.nytimes.com/2008/03/03/business/03juran.html|title=Joseph Juran, 103, Pioneer in Quality Control, Dies|last1=Bunkley|first1=Nick|date=March 3, 2008|work=New York Times|accessdate=25 January 2018|archiveurl=https://web.archive.org/web/20170906182706/http://www.nytimes.com/2008/03/03/business/03juran.html|archivedate=September 6, 2017}}
2. ^{{cite journal|last1=Box|first1=George E.P.|last2=Meyer|first2=R. Daniel|date=1986|title=An Analysis for Unreplicated Fractional Factorials|journal=Technometrics|volume=28|issue=1|doi=10.1080/00401706.1986.10488093}}
3. ^{{cite news|url=https://www.nytimes.com/2008/03/03/business/03juran.html|title=Joseph Juran, 103, Pioneer in Quality Control, Dies|last=Bunkley|first=Nick|date=March 3, 2008|work=The New York Times|postscript=}}
4. ^{{Cite news|url=https://www.entrepreneur.com/article/229294|title=The 80/20 Rule of Sales: How to Find Your Best Customers|last=Marshall|first=Perry|date=2013-10-09|work=Entrepreneur|access-date=2018-01-05|language=en}}
5. ^{{cite book|title=The 80/20 Principle : the Secret of Achieving More with Less|last1=Koch|first1=Richard|date=1998|publisher=Doubleday|isbn=9780385491747|location=New York}}
6. ^{{cite web|url=https://arxiv.org/PS_cache/cond-mat/pdf/0412/0412004v3.pdf|title=Power laws, Pareto Distributions, and Zipf's law|last=Newman|first=MEJ|page=11|access-date=10 April 2011}}
7. ^{{citation|title=Translation of Manuale di economia politica ("Manual of political economy") |first1=Vilfredo|last1=Pareto|first2=Alfred N.|last2=Page|publisher=A.M. Kelley|year=1971|isbn=978-0-678-00881-2|postscript=}}
8. ^{{citation|first=Xabier|last=Gorostiaga|title=World has become a 'champagne glass' globalization will fill it fuller for a wealthy few|journal=National Catholic Reporter|date=January 27, 1995|postscript=}}
9. ^{{citation|author=United Nations Development Program|title=1992 Human Development Report|year=1992|location=New York|publisher=Oxford University Press|postscript=}}
10. ^{{citation|url=http://hdr.undp.org/en/reports/global/hdr1992/chapters/|title=Human Development Report 1992, Chapter 3|accessdate=2007-07-08|postscript=}}
11. ^Curtis Dubay (May 4, 2009) [https://www.heritage.org/poverty-and-inequality/report/the-rich-pay-more-taxes-top-20-percent-pay-record-share-income-taxes The Rich Pay More Taxes: Top 20 Percent Pay Record Share of Income Taxes], Heritage.org, accessed 12 April 2018
12. ^Laura Sanders (April 6, 2018) [https://www.wsj.com/articles/top-20-of-americans-will-pay-87-of-income-tax-1523007001 Top 20% of Americans Will Pay 87% of Income Tax], Wall Street Journal, accessed 12 April 2018
13. ^Emerging Technology from the arXiv (March 1, 2018) [https://www.technologyreview.com/s/610395/if-youre-so-smart-why-arent-you-rich-turns-out-its-just-chance/ If you’re so smart, why aren’t you rich? Turns out it’s just chance.], TechnologyReview.com, accessed 1 January 2019
14. ^1 {{citation|first1=M.|last1=Gen|first2=R.|last2=Cheng|title=Genetic Algorithms and Engineering Optimization|location=New York|publisher=Wiley|year=2002|postscript=}}
15. ^{{citation|url=http://www.crn.com/news/security/18821726/microsofts-ceo-80-20-rule-applies-to-bugs-not-just-features.htm|title=Microsoft's CEO: 80–20 Rule Applies To Bugs, Not Just Features|first=Paula|last=Rooney|date=October 3, 2002|publisher=ChannelWeb|postscript=}}
16. ^Pressman, Roger S. (2010). Software Engineering: A Practitioner's Approach (7th ed.). Boston, Mass: McGraw-Hill, 2010. {{ISBN|978-0-07-337597-7}}.
17. ^{{citation |url= http://speedendurance.com/2008/11/20/training-and-the-80-20-rule-of-paretos-principle/ |title=Training and the 80-20 rule of Pareto’s Principle }}
18. ^Jeff Zimmerman (Jun 4, 2010). [https://www.beyondtheboxscore.com/2010/6/4/1501048/applying-the-parento-principle-80 Applying the Pareto Principle (80-20 Rule) to Baseball], BeyondTheBoxScore.com, accessed 12 April 2018
19. ^{{cite book |last=Woodcock |first=Kathryn |title=Safety Evaluation Techniques |year=2010 |publisher= Ryerson University |location= Toronto, ON |pages=86 |url= http://www.ryerson.ca/woodcock/}}
20. ^{{cite web|title=Introduction to Risk-based Decision-Making |url= http://www.uscg.mil/hq/cg5/cg5211/docs/RBDM_Files/PDF/RBDM_Guidelines/Volume%202/Volume%202-Chapter%206.pdf |work=USCG Safety Program |publisher= United States Coast Guard |accessdate= 14 January 2012}}
21. ^{{citation|title=The Pareto Principle of Prediction|url=https://www.pinnacle.com/en/betting-articles/betting-strategy/the-pareto-principle-of-prediction}}
22. ^{{Citation|last=Epstein|first=Joshua|title=Growing Artificial Societies: Social Science from the Bottom-Up|url=https://books.google.com/?id=xXvelSs2caQC|page=208|year=1996|postscript=|publisher=MIT Press|isbn=0-262-55025-3|last2=Axtell|first2=Robert}}
23. ^{{Cite book|url=https://books.google.co.in/books?id=QtVmCgAAQBAJ&pg=PA8&lpg=PA8&dq=The+Pareto+principle+has+many+applications+in+quality+control&source=bl&ots=qFmwW19c5q&sig=4f0n7ESBCiqhG5xY7ri0NXX5fD0&hl=en&sa=X&ved=0ahUKEwiFo4_YpN7YAhULNbwKHeEQA044ChDoAQg0MAI#v=onepage&q=The%20Pareto%20principle%20has%20many%20applications%20in%20quality%20control&f=false|title=The Pareto Principle for Business Management: Expand your business with the 80/20 rule|last=50MINUTES.COM|date=2015-08-17|publisher=50 Minutes|isbn=9782806265869|language=en}}
24. ^{{harvtxt|Rushton|Oxley|Croucher|2000}}, pp. 107–108.
25. ^Myrl Weinberg: In health-care reform, the 20-80 solution | Contributors | projo.com | The Providence Journal {{webarchive|url=https://web.archive.org/web/20090802002952/http://www.projo.com/opinion/contributors/content/CT_weinberg27_07-27-09_HQF0P1E_v15.3f89889.html|date=2009-08-02}}
26. ^{{cite web|url=http://www.projo.com/opinion/contributors/content/CT_weinberg27_07-27-09_HQF0P1E_v15.3f89889.html|archiveurl=https://archive.today/20090802002952/http://www.projo.com/opinion/contributors/content/CT_weinberg27_07-27-09_HQF0P1E_v15.3f89889.html|deadurl=yes|title=Myrl Weinberg: In health-care reform, the 20-80 solution - Contributo…|date=2 August 2009|archivedate=2 August 2009|website=archive.li}}
27. ^{{cite web |last1=Sawyer and Claxton |first1=Bradley and Gary |title=How do health expenditures vary across the population? |url=https://www.healthsystemtracker.org/chart-collection/health-expenditures-vary-across-population/#item-discussion-of-health-spending-often-focus-on-averages-but-a-small-share-of-the-population-incurs-most-of-the-cost_2016 |website=Peterson-Kaiser Health System Tracker |publisher=Peterson Center on Healthcare and the Kaiser Family Foundation |accessdate=13 March 2019}}
28. ^{{cite journal|last1=Galvani|first1=Alison P.|last2=May|first2=Robert M.|year=|title=Epidemiology: Dimensions of superspreading|url=|journal=Nature|volume=438|issue=|pages=293–295|doi=10.1038/438293a|pmid=16292292}}
29. ^{{cite journal|last1=Lloyd-Smith|first1=JO|last2=Schreiber|first2=SJ|last3=Kopp|first3=PE|last4=Getz|first4=WM|year=2005|title=Superspreading and the effect of individual variation on disease emergence|url=|journal=Nature|volume=438|issue=|pages=355–359|doi=10.1038/nature04153|pmid=16292310}}
30. ^{{Citation|last=Nicola|first=Davis|title='High social cost' adults can be predicted from as young as three, says study|url=https://www.theguardian.com/science/2016/dec/12/high-social-cost-adults-can-be-identified-from-as-young-as-three-says-study|year=2016|postscript=|publisher=The Guardian}}
31. ^{{Cite news |url=https://www.nytimes.com/1988/05/01/business/a-tight-squeeze-at-video-stores.html |title=A Tight Squeeze at Video Stores |last=Kleinfield |first=N. R. |date=1988-05-01 |work=The New York Times |access-date=2019-02-08 |language=en-US |issn=0362-4331}}
32. ^{{Citation|last=Bak|first=Per|title=How Nature Works: the science of self-organized criticality|page=89|year=1999|publisher=Springer|isbn=0-387-94791-4|authorlink=Per Bak}}
33. ^{{Citation|last=Taleb|first=Nassim|title=The Black Swan|pages=229–252, 274–285|year=2007|postscript=|authorlink=Nassim Taleb}}
34. ^{{cite web|url=http://www.poorcity.richcity.org/calculator/?quantiles=82.4,17.6%7C17.6,82.4|title=On Line Calculator: Inequality|website=www.poorcity.richcity.org}}

Further reading

  • {{Citation |last=Bookstein |first=Abraham |authorlink= |year=1990 |title=Informetric distributions, part I: Unified overview |journal=Journal of the American Society for Information Science |volume=41 |issue= 5|pages=368–375 |doi=10.1002/(SICI)1097-4571(199007)41:5<368::AID-ASI8>3.0.CO;2-C |url= |accessdate= |quote= |postscript= }}
  • {{Citation |authors=Klass, O. S.; Biham, O.; Levy, M.; Malcai, O.; Soloman, S. |year=2006 |title=The Forbes 400 and the Pareto wealth distribution |journal=Economics Letters |volume=90 |issue=2 |pages=290–295 |doi=10.1016/j.econlet.2005.08.020 |url= |accessdate= |quote= |postscript= }}
  • {{Citation |title=The 80/20 Principle: The Secret of Achieving More with Less |last=Koch |first=R. |authorlink= |year=2001 |publisher=Nicholas Brealey Publishing |location=London |isbn= |pages= |url=https://www.scribd.com/doc/3664882/The-8020-Principle-The-Secret-to-Success-by-Achieving-More-with-Less |postscript= }}
  • {{Citation |title=Living the 80/20 Way: Work Less, Worry Less, Succeed More, Enjoy More |last=Koch |first=R. |authorlink= |year=2004 |publisher=Nicholas Brealey Publishing |location=London |isbn=1-85788-331-4 |pages= |url= |postscript= }}
  • {{Citation |last=Reed |first=W. J. |authorlink= |year=2001 |title=The Pareto, Zipf and other power laws |journal=Economics Letters |volume=74 |issue=1 |pages=15–19 |doi=10.1016/S0165-1765(01)00524-9 |url= |accessdate= |quote= |postscript= }}
  • {{Citation |doi=10.1016/0094-1190(80)90043-1 |authors=Rosen, K. T.; Resnick, M. |year=1980 |title=The size distribution of cities: an examination of the Pareto law and primacy |journal=Journal of Urban Economics |volume=8 |issue= 2|pages=165–186 |id= |url= |accessdate= |quote= |postscript= }}
  • {{citation |title=The handbook of logistics and distribution management |last1=Rushton |first1=A. |last2=Oxley|first2= J.|last3= Croucher|first3= P. |year=2000 |edition=2nd |publisher=Kogan Page |location=London |isbn=978-0-7494-3365-9 |postscript=}}.

External links

{{Commons category|Pareto principle}}
  • [https://www.paretorule.cf/?m=1 ParetoRule.cf : Pareto Rule]

[https://www.paretorule.cf/2018/12/the-pareto-Rule.html?m=1 ParetoRule.cf : The Pareto Rule]

  • About.com: Pareto's Principle
  • [https://web.archive.org/web/20080528063231/http://www.ma.hw.ac.uk/~des/HWM00-26.pdf Wealth Condensation in Pareto Macro-Economies]
  • The Pareto Principle: Accomplishing goals with purpose

6 : Statistical laws|Rules of thumb|Tails of probability distributions|Statistical principles|Adages|Vilfredo Pareto
随便看

　

开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。

　

Copyright © 2023 OENC.NET All Rights Reserved
京ICP备2021023879号 更新时间：2024/11/11 16:58:02