That adequate-funding level, weighted for things like number of special education students and children living in poverty, was determined by a 2007 independent study commissioned by the Pennsylvania legislature. The study concluded that the state is dramatically underinvesting in education.
In 2009-10, the last year for which data are available, Philadelphia's peers on average spent about $13,308 per student, but needed $15,189 per student to achieve adequacy. Philadelphia spent $11,417 per student, but would have had to spend $16,895 per student to achieve adequacy.
The peer group to which the researchers compared Philadelphia includes 23 high-poverty districts, including William Penn and Southeast Delco locally.
Even given its $5,478-per-student adequacy gap, Philadelphia still produced slightly better state-test results than districts that spent more money.
That achievement is relative, though. Philadelphia performed better, but only about half its students read and do math on grade level.
It wasn't immediately clear what Philadelphia is doing differently to achieve those results, Steinberg said in an interview.
"More research is needed to better understand how these districts are using their resources, but the evidence certainly suggests that Philadelphia is a good investment possibility for the state given what they're doing with their current resources," Steinberg said.
Superintendent William R. Hite Jr. said, "Philadelphia is a story where you've always had to do more with less. . . . The little money we have, we are focusing on schools and classrooms. Think of the possibilities if we were funded at a level suggested in this study."
Steinberg, who will continue to examine the issue, said the findings were "surprising, given the story that's told about Philadelphia, that it's a wasteful place, that it's a place where additional spending is not going to help the students."
He noted that the year his figures come from - 2009-10 - was a relatively flush time for the district. The district had hundreds of millions of federal stimulus dollars that year, and the legislature under Gov. Rendell attempted to make up some of the adequacy shortfall.
"I suspect that if anything," Steinberg said, "the adequacy gap is worse in Philadelphia now."