Pareto Charts For Quality in Projects

Pareto Charts are loosely derived from the Pareto Principle (also known as the 80 20 rule). The Pareto Principle states that 80% of the results come from 20% of the causes. Sometimes you might see this stated as 80% of the results come from 20% of the effort/work. The principle is named from Vilfredo Pareto who observed that in Italy, 20% of the people owned 80% of the land.

From a quality perspective, Pareto Charts are related to the Pareto Principle in that they can be used to show you the 20% of the defects that are causing 80% of the issues being reported or experienced. They are used as part of Six Sigma to aid in the identification of root causes. What this means is that Pareto Charts can be used to indicate the 20% of issues causing you 80% of the pain.

A Pareto Chart contains two vertical axes and one horizontal axis. The horizontal axis shows the categories of issues. The two horizontal axes show the number of occurrences of an issue, and also the contribution to total.

To collect the data to create your own Pareto Chart in Microsoft Excel or some other package you can follow the following steps: