Courts allow school districts to take demographic information into consideration when drawing school attendance zones. But because the concept of the neighborhood school is so strong, school districts tend to shy away from using that power. A common result is schools that reflect neighborhood segregation.
Neighborhoods in the Richardson ISD range from almost all white to almost all minority, with everything in between. How do the schools in those neighborhoods compare with their surrounding neighborhoods?
Vox offers an online tool that lets us see the relationship of RISD's attendance boundaries and the underlying segregation of the neighborhoods surrounding each school. Go ahead and play with it. There's a lot of interesting data visualizations you can do with it. Here are two graphs that tell the story.
The first graph is hypothetical. It shows how schools would be graphed if RISD created attendance zones that exactly replicate neighborhood segregation. Every circle represents a school. As you would expect for this hypothetical situation, every circle falls exactly on the line for which school segregation exactly matches the segregation of its neighborhood.
The second graph is the actual situation. Notice that circles (schools) have shifted up or down, indicating either more or less segregation than the surrounding neighborhood. But the movement is slight and seemingly random. The fit line hardly moves at all.
Here's the thing. If RISD used attendance boundaries to reduce segregation, the fit line itself would get flatter. That is, the circles on the left would all move up and the circles on the right would all move down. In the actual case, the slope of the line remains the same. There's not much difference between the hypothetical situation and the actual case.
In other words, RISD is replicating neighborhood segregation in its schools. Whether you think this is good (i.e., schools should not be used as a tool to reduce racial segregation) or bad (school districts should use this power) is a political decision. Note that the introduction of magnet schools, charter schools, private schools, vouchers, etc., into this discussion complicates the matter, making it harder to predict how redistricting would affect results, even if a school board had the political will to try to use this power to reduce racial segregation.