The Gender-related Development Index (GDI) is a measure of how well countries are doing in terms of providing equal opportunities and living standards for men and women. It looks at four different things: health, education, economy and politics. For each of these things, it compares how men and women are doing, so that countries can see how equal their lives are. For example, if men and women in a country had the same access to healthcare and education, then the GDI would be higher than if they didn't. The GDI helps countries see how they can improve the lives of their citizens and make sure everyone has the same rights and opportunities.