Gender parity index (GPI) is a number that lets us know how equal men and women are in a certain area. It looks at things like the number of girls and boys in school, how many women have jobs, and how much they get paid. The GPI can range from 0 to 1. The closer it is to 1, the more gender-equal a country or region is. A GPI of 0 means that the men and women are completely not equal.