The Pareto priority index (PPI), so named because of its connection with the Pareto principle

Pareto principle

The Pareto principle states that, for many events, roughly 80% of the effects come from 20% of the causes.Business-management consultant Joseph M...

, which is in turn named after the economist Vilfredo Pareto

Vilfredo Pareto

Vilfredo Federico Damaso Pareto , born Wilfried Fritz Pareto, was an Italian engineer, sociologist, economist, political scientist and philosopher. He made several important contributions to economics, particularly in the study of income distribution and in the analysis of individuals' choices....

, can be used to prioritize several (quality improvement) projects. It is especially used in the surroundings of six sigma

Six Sigma

Six Sigma is a business management strategy originally developed by Motorola, USA in 1986. , it is widely used in many sectors of industry.Six Sigma seeks to improve the quality of process outputs by identifying and removing the causes of defects and minimizing variability in manufacturing and...

 projects. It has first been established by AT&T

AT&T

AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...

.

The PPI is calculated as follows:

A high PPI suggests a high project priority.