July 28, 2013
Arizona’s education problem is not caused by its well-off school districts. Most but not all perform at or above expectations for their favorable socio-economic conditions.
Arizona’s education problem is caused by its less well-off districts. Some perform above expectations in light of their difficult socio-economic conditions. But others perform significantly worse.
The red line – computed from a regression analysis of the composite state test scores of the 74 Arizona districts with three or more elementary schools – shows the expected scores at every socio-economic level. Each dot is the actual result for a district.
The line looks as if it wants to shift upward by five points or so to meet many of the dots. But the low results for the low-income, low-performing schools on the lower right side of the graph drag it down, drag down the slope of the line, and drag down overall student achievement in Arizona.
Thinking Arizona’s statistical analysis reveals that each increase of 25 percentage points in the number of elementary school students eligible for subsidized lunch costs districts on average about 10 points in their education scores.
Districts with 25 percent of their elementary students on the lunch program score on average 141 points on the state grading system. Districts with 50 percent of students on subsidized lunch average 131 points. Districts with 75 percent are down at 121 points.
This analysis differs a little from the usual ones, however. Districts are judged here not by their composite scores but by the differential between actual performance and the expected performance for districts of their socio-economic characteristics – as reflected by the red line.
Those in the top 10 percent of differences above the line are judged to be excelling in respect to their circumstances, while those in the top 25 percent are overperforming. Those in the middle 50 percent are on par. Those in the bottom 25 percent of differences below the line are underperforming, with those in the bottom 10 percent failing.
Consider for instance the difference between the Madison district on the near northside of Phoenix and the Sahuarita district south of Tucson. The two have similar socio-economic circumstances but different levels of performance.
The Madison district on the near north side of Phoenix would be expected to score 133 with 45 percent of its elementary students on subsidized lunch. It overperformed that with an actual score of 140. By comparison, the Sahuarita district south of Tucson should have scored 135 with 39 percent on the lunch program. But it failed to come close with an actual score of 120.
The high of Madison and the low of Sahuarita are a little unusual. Most of the 22 districts at the top of the socio-economic chain – meaning those with less than half their students on subsidized lunch – are clustered close to the line. As such, they’re on par with the scores one would expect of them.
Against this tougher standard, only Madison and the Vail School District on the southeast side of Tucson overperform.
Vail actually came within a whisker of excelling with a score of 149. That’s akin to the scores for the upper-crust Cave Creek and Catalina Foothills districts, even though those two enclaves have much less poverty. With 29 percent of its students of subsidized lunch, Vail would be expected to have come in at just 140 points.
Meanwhile, three districts – Sierra Vista, Flagstaff, and J.O. Combs in the San Tan Valley – underperformed the expectations that come with better demographics, although not to the extent of Sahuarita.
Those are the well-off districts. Most of the state’s districts are of the poorer variety.
Unlike the 22 better-off districts that pretty much cluster along the line of expectations, the 52 poorer districts are all over the graph. More either substantially over- or underperformed than were on par.
Seven excelled, scoring well above what one would expect of districts in their circumstances. As Stephen Trejo, principal of A-rated C.E. Rose Elementary in Tucson, has said: “It can be done.”
The best of these is the Nogales school district. With 83 percent of its elementary population on the lunch program, one would have expected Nogales to score about 118 points. It compiled 143.
Among the others that rose well above expectations was a Nogales neighbor, the Santa Cruz Valley district. The list also includes the Laveen, Osborn and Balsz districts, all in the Greater Phoenix area, along with the Humboldt district in the Prescott Valley and the Somerton district adjacent to Yuma.
Nine more of these districts overperformed. And 22 were on par with the lowered expectations. The latter group includes the sometimes vilified Tucson Unified School District with a state score of 118. That’s low on an absolute basis but with three-quarters of its students on subsidized lunch, TUSD was within 3 points of what would be expected.
A number of districts, however, fell short even when expectations are lowered to reflect their circumstances. Eight underperformed. Another six failed.
The latter group, comprised of the Tuba City, Window Rock, Parker, Chinle, Coolidge and White River districts, was shy of the lowered expectations by 18 to 33 points. Most of those are heavily Native American, suggesting that another analytical allowance may be in order.
Regardless, their students were challenged coming into school. They’ll also be challenged going out into the world.
– Richard Gilman
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