Introduction: The United States public school system is becoming increasingly diverse, with more than 50% of students in public elementary and high schools coming from racial and ethnic minority backgrounds (U.S. Department of Education, 2016). However, the rise in student diversity has not been matched by an increase in teacher diversity, with teachers from racial and ethnic minority backgrounds comprising less than 20% of the teaching force (U.S. Department of Education, 2016). These large discrepancies in student and teacher diversity have led many organizations and policymakers to call for action to increase recruitment of racial and ethnic minority teachers as they advocate for the importance of teacher diversity in helping increase teacher quality and close achievement gaps (National Collaborative on Diversity in the Teaching Force, 2004). Using data from the National Center for Education Statistics, this data visualization highlights the dramatic changes in student diversity in the United States across the years and contrasts them with the correspondingly small increases in teacher diversity. A diversity index \((D_c)\) was calculated from information on the total number of racial/ethnic groups \((g)\) and the proportion of teachers/students \((p_i)\) who belong to each racial/ethnic group \((i)\) using the following equation (Simpson, 1949):
$$D_c = 1-\sum_{i=1}^gp_i^2 $$
The formula gives the probability that two randomly selected students/teachers from the United States (in the barplots) or from each state (in the map) are from a different race/ethnicity. Scores can range from 0 to 1, with higher numbers indicating increased student/teacher diversity. For example, in the map, a state with 50% White and 50% Black students would have a student diversity index of 0.5. A state with 25% White, 25% Black, 25% Hispanic, and 25% Asian teachers would have a student diversity index of 0.75.
Data visualization: The visualizations were created using d3 in javascript with some CSS for styling. For the barplots, you can press the buttons underneath the plots to switch between displaying diversity index or racial/ethnic breakdown data for students (left) and teachers (right). You can also hover over the bars to see details for the specific numbers. For the map, you can press the "play" button on the timeline to automatically go through diversity data through the years, or drag the cursor on the timeline at any point to choose a specific year. You can also mouse over a state to show the specific student diversity index for that state on a given year.