How diverse is your student body? A tour through some classrooms may give you some idea. But how diverse is your student body in relation to the school across town? To answer that question, you need a more precise measure. Enter Ethnic Diversity Index (EDI), a reflection of how evenly distributed your students are among the race/ethnicity categories reported to the California Department of Education.
The precise formula can be found on Ed-Data’s old website, but it is obviously of little value until put into a computational environment. Here’s one possible instantiation in R:
EDI is calculated on a 0-100 scale: indices closer to zero indicate less diversity, and indices approaching 100 indicate great diversity. As Ed-Data explains:
…a school that had exactly 1/8th of its students in each of the eight categories would have an Ethnic Diversity Index of 100, and a school where all of the students are the same ethnicity would have an index of 0. In reality, of course, no school has an index of 100 (although a few have diversity indices of 0). Currently the highest index for a school is 76.
Let’s test our function with some simulated data of a perfectly balanced student body:
Precisely what we wanted.