Two days ago I published a data series ranking the performance of Virginia’s school systems based upon a composite score for the Standards of Learning pass rates in all grades. While interesting, the list did not lend itself to any policy conclusions. Under-performing school systems can always say, “It’s not our fault. So many of our kids come from dysfunctional families. We’re educators, not social workers.”
“In an ideal world,” I concluded, “there would be some way to measure ‘educational value added’ so we could determine whether educators were doing a good job or not.”
Enter John Butcher, a long-time reader and once-in-a-blue-moon contributor. The usual proxy measure for socio-economic status is the percentage of students eligible for for free and reduced lunches. He took the liberty of mapping those percentages against the composite scores in the previously published blog post. Here are the results:
Graphic credit: John Butcher
Clearly, there is a significant relationship between socio-economic status and SOL pass rates. But just as clearly, other factors come into play. Diamonds above the gold trendline perform better than expected, while those below the line perform worse.
The red diamonds represent (from the left) Hampton, Newport News, Norfolk and Petersburg. The gold square is the City of Richmond, which not only has the lowest pass rate in the state but grossly under-performs the trendline. The yellow diamond is Danville, which shows that “a city with a large F/R percentage can considerably outperform the trendline.” The green diamond is Charles City County, “which took a real tumble with the new math and reading tests.”
On the theory that variation above and below the trendline is probably related to either (1) spending levels or (2) the quality of school management and governance, I suspect readers would like to know whether their school systems perform above or below expectations.
Now, if only I had the technology that would allow readers to identify each diamond by rolling over the cursor. Does anyone have that capability or know where I can obtain it?
Update: Butcher informs me, based upon communication with a source of his at the Charles City County school board, that Charles City might have supplied erroneous data to the state.
— JAB
