When we talk about K-12 education spending inequality, we're usually talking about differences in resources between high- and low-poverty districts within states. But spending levels also vary between states, and that too matters for overall spending inequality in the U.S. How has this changed over the past 25 years? In other words, does K-12 spending vary more between states than it did a quarter century ago?
Let’s take a look at one simple way to visualize this trend. In the graph below, each blue circle is a state, and there one set of 51 states (including D.C.) for each year between 1993 and 2018 (the horizontal axis). On the vertical axis is total current spending in each state, predicted for a district in each state with a 10 percent Census child poverty rate (the graph is very similar regardless of poverty level). These spending levels also control for regional wage variation, district size, and population density, all of which affect the “value of the education dollar.” This allows for a better comparison between states (e.g., it costs more, on average, to hire teachers in Connecticut than in Alabama). The red plus signs within each year represent the unweighted average spending level across all states. These data are from the School Finance Indicators Database.
Our focus here is on the “spread” of states (blue circles) within each column (i.e., within each year). A larger spread, of course, represents greater variation (and, roughly speaking, more interstate inequality). The trend over time is a bit striking.