The logic and power of expert sampling lie in selecting people to study or interview who are especially knowledgeable about a topic and are willing to share their knowledge. Expert sampling involves identifying key informants who can inform an inquiry through their knowledge, experience, and expertise. Experts can provide valuable insights into the root of problems, what has been tried and failed, what has been tried and worked, and future trends to watch.

Using key informants began with ethnographers who needed indigenous expertise to help them understand cultures other than their own. Sociologists developed focus groups and interview methods with key informants to study issues in their own countries. A carefully selected group of naturally acute observers and well-informed people can serve as a panel of ...