For a generation now, school reform has meant top-down mandates for what students must be taught, enforced by high-stakes standardized tests and justified by macho rhetoric — “rigor,” “raising the bar,” “tougher standards.”

Here’s a thought experiment. Suppose that next year virtually every student passed the tests. What would the reaction be from politicians, businesspeople, the media? Would these people shake their heads in admiration and say, “Damn, those teachers must be good!”?

Of course not. Such remarkable success would be cited as evidence that the tests were too easy. In the real world, when scores have improved sharply, this has indeed been the reaction. For example, when results on New York’s math exam rose in 2009, the chancellor of the state’s Board of Regents said, “What today’s scores tell me is not that we should be celebrating,” but instead “that New York State needs to raise its standards.”

The inescapable, and deeply disturbing, implication is that “high standards” really means “standards that all students will never be able to meet.” If everyone did meet them, the standards would just be ratcheted up again — as high as necessary to ensure that some students failed.