There are two broad approaches to measuring segregation: measures of exposure and measures of evenness. Exposure indices measure the school composition that the average student of a given racial group is “exposed” to — e.g., a White-Hispanic exposure value of 0.19 means that the average White student attends a school that is 19% Hispanic. Interpreting exposure measures as indicators of segregation is difficult without taking the population composition into account. In this example, an exposure value of 0.19 would suggest fairly high segregation in a population that is 40% Hispanic — Hispanic students are underrepresented in White students’ schools by half their population share— while in a 10% Hispanic population, 0.19 would suggest racial integration — Hispanic students are overrepresented in White students’ schools.
Measuring Segregation With The Normalized Exposure Index