Otis Dudley Duncan is a special grown-up who studied people and where they live. He wanted to learn about different kinds of people and what makes them unique. He also wanted to understand how people's homes and neighborhoods affect them. He spent a lot of time talking to people and looking at information to figure out how everything works together.
He was very good at looking at all of the information he gathered and turning it into numbers and charts so other grown-ups can understand it too! He even helped create something called the "Index of Concentration" which shows how much different races or ethnic groups live in certain areas.
Otis Dudley Duncan was a very important grown-up who helped us learn more about people and where they live. Even though he is not with us anymore, his research is still used today to help us understand and make things better for everyone.