Pareto Charts For Quality in Projects

Pareto Charts loosely derive from the 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 who observed that in Italy, 20% of the people owned 80% of the land.

From a quality perspective Pareto:

Pareto Charts are related to the Principle in that they can use. To show you the 20% of the defects that are causing. 80% of the issues report or experience. They are used as part of Six Sigma to aid in the identification of root causes.

What this means is that Charts can use 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.

Determine your Pareto.

Here you simply need to define a number of buckets into which issues can place. For example, if you were examining issues found with new cars you might have buckets for Electronics, Steering, Engine, Cosmetic, etc. You should always aim to have less than 10 buckets in total. In that way the big trends won’t get miss.

Now go through your issues one at a time and add them to one of the buckets you have already defined. Don’t worry if you need to rename your buckets as you Pareto.


That’s it:

Pareto You should now have all the data you need to create your chart and determine which area of issues to tackle first to have the most dramatic impact on quality within your project.

For example, if you were examining issues found with new cars you might have buckets for Electronics, Steering, Engine, Cosmetic, etc. You should always aim to have less than 10 buckets in total. To collect the data to create your own Pareto Chart in Microsoft Excel or some other package you can follow the following steps. The two horizontal axes show the number of occurrences of an issue, and also the contribution to total.

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