Performance Management: Pareto Principle (Definitions)

"A rule that posits that 80 percent of business activity comes from about 20 percent of the customers or clients. Named for Vilfredo Pareto, an Italian economist." (Robert McCrie, "Security Operations Management 2nd Ed.", 2006)

"The general observation that a small amount of effort can derive a great amount of rewards. Also known as the 80/20 rule because it often is stated as 80 percent of the results come from 20 percent of the effort." (Craig S Mullins, "Database Administration: The Complete Guide to DBA Practices and Procedures" 2nd Ed., 2012)

"Also known as the 80/20 rule, Pareto’s principle holds that a small number of causes may account for the vast majority of observed instances. For example, a small number of rich people account for the majority of wealth. Likewise, a small number of diseases account for the vast majority of human illnesses. A small number of children account for the majority of the behavioral problems encountered in a classroom. A small number of states or provinces contain the majority of the population of a country. A small number of books, compared with the total number of published books, account for the majority of book sales. Sets of data that follow Pareto’s principle are often said to follow a Zipf distribution, or a power law distribution. These types of distributions are not tractable by standard statistical descriptors. For example, simple measurements, such as average and standard deviation, have virtually no practical meaning when applied to Zipf distributions. Furthermore, the Gaussian distribution does not apply, and none of the statistical inferences built upon an assumption of a Gaussian distribution will hold on data sets that observe Pareto’s principle." (Jules H Berman, "Principles of Big Data: Preparing, Sharing, and Analyzing Complex Information", 2013)

"In the Dynamic Systems Development Method, the assumption that 80-percent of an application’s features will take 20-percent of the project’s total time to implement. (The 80/20-rule often applies to other situations, too. For example, 80-percent of the bugs are usually contained in 20-percent of the code.)" (Rod Stephens, "Beginning Software Engineering", 2015)

"Better known as the 80/20 rule, this observation is that 20% of things will make 80% of difference, i.e. 20% of customers account for 80% of profits (and vice versa)." (Duncan Angwin & Stephen Cummings, "The Strategy Pathfinder" 3rd Ed., 2017)

"Doctrine which shows that approx. 20% of causes create 80% of problems. Also known as 80/20 rule." (Albert Lester, "Project Management, Planning and Control" 7th Ed., 2017)

"Sometimes called the Pareto distribution, the notion that to be strategic organisations should focus on the 20% of the business/customers/suppliers/stakeholders that make 80% of the difference to the business. The potential weakness of using this logic is that it may not adequately reflect dynamic situations." (Duncan Angwin & Stephen Cummings, "The Strategy Pathfinder" 3rd Ed., 2017)

"A general rule of thumb that suggests that 80 percent of the cost comes from 20 percent of the cost factors, or that 80 percent of the value is generated by 20 percent of the people. Also called the 80/20 rule. Used to guide system designers to focus on the aspects that matter most to outcome." (O Sami Saydjari, "Engineering Trustworthy Systems: Get Cybersecurity Design Right the First Time", 2018)