The 80/20 Rule — Pareto Principle

80% of the the outcomes come from 20% of the causes.

The 80/20 rule, commonly referred to as the Pareto Principle or Law of Vital and Trivial many is a common term amongst the realm of business. Most often thought of as a rule of thumb. It is an interesting concept that proves to be rather correct. The 80/20 rule works in economics, engineering, and even user experience design.

Created by economist Vilfedo Pareto the 80/20 rule stated that 80% of the land in Italy was owned by 20% of the population. His discoveries came from observation of his garden. After a growing season Pareto was able to determine that 20% of the pea pods produced 80% of the peas.

When applied to information technology and software development the 80/20 rule essentially concludes that the majority of defects are from the minority of variables in a system. In practice 20% of the features or functions used in a digital product are only used 80% of the time. Design and testing should then be focused on that 20%. The less used functions can either be hidden or removed.

As user experience designers we can use the 80/20 rule in a variety of ways. Almost as many ways as one could layout a dashboard. The 80/20 rule can come in handy when meeting with stakeholders or business owners, or even when deciding what parts of a system should be made better.

The 80/20 rule is a great base point for weeding out unnecessary things and focusing on those of utmost importance.

References:
Pareto principle
https://en.wikipedia.org/wiki/Pareto_principle

Pareto’s Principle — The 80–20 Rule
http://management.about.com/cs/generalmanagement/a/Pareto081202.htm

80–20 Rule
http://www.investopedia.com/terms/1/80-20-rule.asp