Source: New York Times.
The New York Times did a deep data dive into "Money, Race and Success: How Your School District Compares." That's the Richardson ISD in the upper middle of the plot of every school district in America. The RISD is a little richer than average as measured by parents' economic status. And it stands in the upper reaches of academic performance of school districts with similar economic status, 0.6 grades ahead of the overall average. What's it all mean?
Notice how the cloud slants from lower left to upper right in the graph. That's a strong correlation between economic status and school performance (there's another graph that colors the school districts by race/ethnicity, showing another strong correlation). Pick a vertical band anywhere along the x-axis. There's a ceiling in academic performance for that economic status. That ceiling slopes upward with economic status. The RISD being near the upper edge of the cloud means it's close to that ceiling for its particular economic status.
If you're a glass half-empty kind of person, you'd complain that the RISD isn't in the far upper right corner of this graph.
If you're a glass half-full kind of person, you'd pat the RISD on the back for being near the upper edge of that cloud, meaning kids in the RISD are outperforming kids who live in similar districts.
To move higher on the scale (i.e., get better academic outcomes), the RISD would have to move to the right on the scale as well (i.e., get richer parents). Assuming the RISD can't just get richer parents, it somehow has to come up with superior educational practices to break through that socioeconomic ceiling and become an outlier in this graph, floating above every other district near its own vertical line. That's difficult (and unlikely). Yet the teachers and administrators are accomplishing much in that direction, which is why the RISD is near the ceiling in the first place. Demography may be destiny, but the RISD seems to be making the most of that demography. It turns out that the glass is more than half full.
P.S. Everything above is contingent on the reliability of the data in that graph. That in turn depends on the existence of and application of standardized tests. There's a growing movement against standardized testing. I have mixed feelings about that. Although it's possible to devote too much time to testing, without testing we'd have no way to judge the effectiveness of our schools. There's a balance needed. If we're too far on the side of testing now, I fear that we're about to swing too far to the other side. And in any case, Texans have always been way too averse to national standards. Without them, there's no direct way to compare how Texas is doing against the rest of the country and the world. Maybe that's the point. But all that's for another discussion.