The Zip Code Effect measured a neighborhood by its money. But there is a friendlier number sitting in every public school's file: the share of its seniors who actually walk across the stage. Graduation rate is wealth's more human cousin, a positive outcome instead of a Census tract. So I asked the obvious question. Does it predict a soccer program's strength any better than the dollar figure does?
Across 237 public programs with eight years of graduation data and a wealth score, neighborhood wealth is the stronger predictor of ELO. Graduation rate trails it, and by a lot on the boys' side.
So if you only get one column to guess a program's rating, keep the wealth score. That is the plain result and I am not going to dress it up. But it is also not the interesting part, because the two numbers turn out to be measuring almost completely different things.
You might expect a school's graduation rate and its neighborhood wealth to move together, rich area, more diplomas. They barely do. Across these programs the two correlate at just 0.15. A school in a modest ZIP can graduate nearly everyone, and a school in a comfortable one can leak seniors out the back. Two schools can share a wealth score and sit a world apart on the diploma line.
Strip out everything graduation rate shares with wealth, and ask whether the leftover still tracks winning. It does. After controlling for neighborhood wealth, graduation rate still holds a 0.29 pull on ELO for girls, and a fainter 0.13 for boys. The signal is modest, but it is real and it is its own. A program's graduation rate is telling the rating something the wealth score never says.
The plainest view: sort the public programs into four groups by graduation rate and read off the average rating of each, with the average neighborhood wealth alongside so you can watch whether the climb is just money in disguise.
The bottom quarter on graduation sits well down the rating scale; the top quarter sits near the top. And the wealth column, on the right, hardly climbs at all across the four rungs, which is the same thing the controlled number said, now in a shape you can see: this ladder is not a wealth ladder wearing a graduation label.
One year of graduation data is noisy, so the numbers above lean on an eight-year average per school. But splitting it back apart, year by year, tells its own story. Run the graduation-to-ELO correlation separately in each cohort from 17-18 through 24-25, and the girls' line holds remarkably still. The boys' line wanders, weak, in the same low band every year.
This is the same split the money reports kept finding, and it shows up here too, on a completely different axis. Whatever a school's graduation rate is capturing, some mix of stability, buy-in, and a place that keeps its kids on track, the girls' game tracks it and holds that track for eight straight years. Sharpen the test and it sharpens the same way: a school's female graduation rate lines up with its girls' ELO at 0.31, while the male rate and boys' ELO manage only 0.19.
The tail is where a correlation earns or loses your trust, so here are the twelve public programs with the lowest graduation rates on record, and where their soccer landed. Most are urban schools in Memphis and Nashville, and their teams mostly sit below the state's middle. But look at the wealth column: it is all over the place. A low graduation rate is not simply a poor one.
| School | County | Grad % | Wealth | Boys | Girls |
|---|
County and wealth are hidden at this width.
Graduation rate does not beat the zip code, but it is not the zip code either. As a raw predictor of soccer strength it comes in behind neighborhood wealth, clearly for the boys and narrowly for the girls. If you only get one number, take the money.
But graduation rate is nearly independent of wealth, and it holds an ELO signal of its own even after wealth is removed, small for the boys and steady for the girls across eight straight cohorts. It is not measuring how rich a community is. It looks more like a measure of how well a school holds itself together, and on the girls' side, the kind of school that graduates its seniors is, a little more often than not, the kind of school that fields a team worth watching.