This latest think-tank report (Return on Educational Investment: A District-by-District Evaluation of U.S. Educational Productivity) concludes that "low productivity costs the nation’s school system as much as $175 billion a year." A separate website even provides an interactive district-by-district evaluation of educational productivity.
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. ...
Without controls on how additional school dollars are spent, more education spending will not automatically improve student outcomes.
I could go on, but you've heard it all before from Heritage, Cato, AEI, etc. This report, however, comes from the lefty, Soros-funded Center for American Progress.