The Pareto Principle holds that for any event (or problem) a small number of factors account for a majority of reasons why the event or problem occurred (80/20 means 80% of the problem is due to 20% of the causes). Using the Pareto Principle allows teams to separate the “Trivial Many (the areas of greatest impact)” from the “Vital Few.” The reader is referred to the Institute for Healthcare Improvement site for complete instructions on building this type of diagram.

This example shows the X-axis with categories and the Y-axis as the measure of interest–in this case, number of babies.