Specifically, the State argues first that fraud and corruption in the community school boards and City school construction spending, rather than the funding system, are the cause of any shortage of inputs. The trial court rejected these arguments (187 Misc 2d at 92, 94) and the Appellate Division likewise rejected the point about construction spending (295 2 at 18) while saying nothing about the community school boards. We thus have no occasion to review either argument. The State argues second that, corruption aside, the Board of Education mismanages the schools, particularly by referring too many students to special education and placing too many of these children in costly full-time segregated settings. The trial court credited evidence that better special education practices could save City schools between $105 and $185 million annually, though some of these savings would be offset by the greater cost of instructing children with special education needs in a mainstream environment (187 Misc 2d at 96-97). The Appellate Division saw the possible savings mounting to "hundreds of millions of dollars, if not one billion dollars" (295 2 at 17) -- a figure exceeding even the $335 million claimed by the State's expert, Dr. Daniel Reschly. We are thus constrained to accept that some saving on special education is possible, a fact that to some extent undermines plaintiffs' argument that the school funding system is unconstitutional because it leaves New York City schools with insufficient funds to provide a sound basic education. But the magnitude of the savings is in dispute. The Appellate Division appears to have arrived at its "billion" simply by taking the number of full-time special education students, assuming that 80 percent could be moved to part-time settings, and multiplying the number of students subject to this move by the $10,000 difference between the cost of full-time and part-time placement. No witness for the State sponsored any such calculation, and there was thus no opportunity to test the Appellate Division's assumptions on which it is based. The available evidence-based conclusions are that over- referral to special education costs City schools somewhere between tens of millions and $335 million. Even the lower of these figures would reflect both resources squandered and the likelihood that many children are badly served and perhaps stigmatized by segregated placements in the special education system in City schools. But, conversely, even savings approaching the higher figure would not necessarily translate dollar-for-dollar into funds free for investment in better inputs, much less into an investment sufficient to relieve the existing systemic educational crisis. In