Pareto Analysis with R

Abstract

Causa latet: vis est notissima. [The cause is hidden, but the result is known.] Ovid 6.1 Introduction Pareto analysis is a technique that can be used in several stages of a Six Sigma project. In the Measure phase of the design, measure, analyze, improve, and control (DMAIC) cycle, we use it to prioritize the possible causes of defects and then focus on the important ones. The basis of Pareto analysis is the Pareto principle, which applies to many processes in real life. Roughly speaking, the Pareto principle states that most effort/benefit (approximately 80%) is due to a limited number of key actions (approximately 20%). It is also known as the 80/20 rule. A search for these key actions is usually made using a Pareto chart, a tool that allows us to see at a glance the results of a Pareto analysis. In this chapter, we review the foundations of Pareto analysis in Sects. 6.2 and 6.2.1. In Sect. 6.3, we apply the Pareto principle to detect important improvement opportunities in a Six Sigma project. We use R to plot Pareto charts in Sect. 6.4. Finally, in Sect. 6.5 we introduce other uses of the Pareto principle within Six Sigma projects.