In 1897, the Italian sociologist and economist Vilfredo Pareto identified a fascinating pattern that came to be known as the Pareto Principle. In a nutshell, it states that 80% of a wide range of things is owned or fueled by 20% of the population or the effort expended. Pareto zeroed in on land ownership, but the potential applications of his principle are far-ranging.

As a physical therapist or physical therapist assistant, you may have born witness to this at your facility, noting that somewhere around 20% of the total diagnoses tend to apply to about 80% of the patients. Go back to when you were a student: Didn't it seem as if 20% of the subject matter made up 80% of the test?

In his 2001 bestseller The 80/20 Principle, author Richard Koch even claimed that 20% of divorced people make up 80% of all divorces, since many of them tend to have multiple disunions under their belt!