Pennsylvania is close to the bottom of the nation in state financial support for public education. For years, we've hovered around 35% of school funding coming from the state.
That means that the effects of local wealth are heightened in the state. Rich districts can afford to pony up tax dollars to make up the difference, and poor districts struggle. In other states, state dollars might obscure the real differences in wealth between rich and poor districts, but in PA, the differences are still right there. Which is why this chart packs a punch. For those of you looking for one more test-score-to-economic-status correlation, here you go. The data and the chart come from the state department. The school ranking is (was, actually, but that's another story) based on the School Performance Profile (SPP) and the SPP, for the fancy language and math involved, was 90% based on Big Standardized Test scores.
So that's what you're seeing when you look at the chart-- the correlation between district wealth and the results of the BS Test. Now, that could be a factor of the socio-economic background of the students taking the test, or it could be a factor of the district budget, or some combination of the two. But the one thing you can't say here is that money doesn't matter. The fewer poor students you serve, the better your test scores. One more indication that using the BS Tests to measure student achievement or school effectiveness or teacher quality is simply bunk. I don't know exactly what it tells us about people who don't know when to use "fewer" instead of "less."