NHS Education for Scotland: Pareto Chart

Summary

A Pareto chart is a type of bar chart in which the factors that contribute to an overall effect are arranged in order from most frequent to least. This ordering helps identify the "vital few" — the factors that warrant the most attention.

It also includes a line showing the cumulative % (so you can see easily for example that the top three causes account for 80% of incidents).

According to the "Pareto Principle," in any group of things that contribute to a common effect, relatively few account for the majority of the effect.

Content

Using a Pareto chart helps a team concentrate its improvement efforts on the factors that have the greatest impact. It also helps a team communicate the rationale for focusing on certain areas.

For example you might want to look at:

• type of safety incidents that occur
• causes of a specific type of problem
• reasons for cancellation.

They are a useful tool not only when identifying opportunities for improvement, but also in drilling down to understand the reasons for special causes on graphs showing counts, percentages and rates.