The Center for American Progress, via a kind reader’s email:

The Wisconsin school systems of Oshkosh and Eau Claire are about the same size and serve similar student populations. They also get largely similar results on state exams-but Eau Claire spends an extra $8 million to run its school system
This report is the culmination of a yearlong effort to study the efficiency of the nation’s public education system and includes the first-ever attempt to evaluate the productivity of almost every major school district in the country. In the business world, the notion of productivity describes the benefit received in exchange for effort or money expended. Our project measures the academic achievement a school district produces relative to its educational spending, while controlling for factors outside a district’s control, such as cost of living and students in poverty.
Our nation’s school system has for too long failed to ensure that education funding consistently promotes strong student achievement. After adjusting for inflation, education spending per student has nearly tripled over the past four decades. But while some states and districts have spent their additional dollars wisely–and thus shown significant increases in student outcomes–overall student achievement has largely remained flat. And besides Luxembourg, the United States spends more per student than any of the 65 countries that participated in a recent international reading assessment, and while Estonia and Poland scored at the same level as the United States on the exam, the United States spent roughly $60,000 more to educate each student to age 15 than either nation.
Our aims for this project, then, are threefold. First, we hope to kick-start a national conversation about educational productivity. Second, we want to identify districts that generate higher-than-average achievement per dollar spent, demonstrate how productivity varies widely within states, and encourage efforts to study highly productive districts. Third–and most important–we want to encourage states and districts to embrace approaches that make it easier to create and sustain educational efficiencies.
This report comes at a pivotal time for schools and districts. Sagging revenues have forced more than 30 states to cut education spending since the recession began. The fiscal situation is likely to get worse before it gets better because the full impact of the housing market collapse has yet to hit many state and local budgets. At a time when states are projecting more than $100 billion in budget shortfalls, educators need to be able to show that education dollars produce significant outcomes or taxpayers might begin to see schools as a weak investment. If schools don’t deliver maximum results for the dollar, public trust in education could erode and taxpayers may fund schools less generously.
While some forward-thinking education leaders have taken steps to promote better educational efficiency, most states and districts have not done nearly enough to measure or produce the productivity gains our education system so desperately needs. Some fear that a focus on efficiency might inspire policymakers to reduce already limited education budgets and further increase the inequitable distribution of school dollars. To be sure, our nation’s system of financing schools is unfair. Low-income and minority students are far more likely to attend schools that don’t receive their fair share of federal, state, and local dollars. But while the issue of fairness must be central to any conversation about education finance, efficiency should not be sacrificed on the altar of equity. Our nation must aspire to have a school system that’s both fair and productive.
Our emphasis on productivity does not mean we endorse unfettered market-based reforms, such as vouchers allowing parents to direct public funds to private schools. Nor do we argue that policymakers should spend less on education. Indeed, we believe neither of these approaches can solve the nation’s pressing education challenges. Transforming our schools will demand both real resources and real reform. As Education Secretary Arne Duncan recently said: “It’s time to stop treating the problem of educational productivity as a grinding, eat-your-broccoli exercise. It’s time to start treating it as an opportunity for innovation and accelerating progress.”

Madison’s results can be seen here. I asked Superintendent Dan Nerad what benefits citizens, students and parents received from Madison’s greater per student spending, then, for example, his former Green Bay school district in this recent interview.
Madison spent $15,241 per student according to the 2009-2010 Citizen’s Budget. I’ve not seen a 2010-2011 version.