Pareto Charts

in Health Care, Tools & Methods, Videos

By David M. Williams, PhD

Harvardx course Practical Improvement Science in Health Care with the Institute for Healthcare Improvement.

Have you ever heard of the 80-20 rule? While its roots are in economics and process improvement, it’s found its way into popular culture. The basic idea is that with everything we are trying to improve, 80% of the problem or opportunity lies with 20% of the reasons. So what is a Pareto chart? Well, let’s take a look.

A Pareto chart is both a bar and a line chart. So we’re going to draw this up. And it has two axes. So there’s the y-axis on the left hand side. We got our x-axis. And then we’ve got another y-axis on the right hand side. On the right hand side is the percentage in which something occurs.

So we’re just going to try to keep it simple here. We’ll put 100%, 50%, and then just down here at 0. On the left hand side, this is the frequency in which an issue occurs. So again, we’ll try to keep it simple here. And we’ll go with 10, 5, and that would be 0. And then along the bottom, we list the categories or defects of issues that we’re seeing. So A, B, C, D, E. And I’ll just put the defects.

Now as we’re tracking our data from a collection form, we’ll look at it and we’ll say, well gosh, how many did we have of each of these? And we try to list these in the order in which is most frequent to least frequent. So it’s showing you from big to small.

So if we think of Defect A, let’s imagine that we had 8 of Defect A. Defect B, we had 5. Defect C, we only had about 3. Defect D, there was maybe 2. And Defect E had 1. So again, we’ll — And then there’s another piece that’s a line chart. And that’s where the percentages come in. And what we’re trying to do is identify what percentage of the total problem is each of the defects, so we can try to see which is the most common to least common. We’re looking for that 80-20 rule.

So imagine we’ve got this line chart. And we’ll just say that, if this is 80 here, if we work on these particular defect, we can expect that we can actually make the biggest improvement in our process. And so it’s a great place for us to start doing our PDSA testing and some of our other tools and methods to identify opportunities for improvement. So the idea here is to look at the issues with the biggest effect — the vital few 20% — and focus your improvements there first. If successful, your initial improvements will make the biggest difference.

Pareto charts are very easy to create in any spreadsheet program and are helpful for converting check sheet and cause and effect data into knowledge. It helps focus improvement efforts on the vital few opportunities for improvement and can help you make a big impact.

If this was helpful, share and include me @DaveWilliamsATX. Sign up here to receive a monthly email from me that includes all my blog posts and other Improvement Science resources I think you’d appreciate.