President Obama's ambitious effort to lift the nation's schools draws heavily from the playbook employed in Chicago and New York City: Test kids more often, open more charter schools and tie teacher pay to student performance.

California's schools and politicians are promptly obliging Washington, like kids lining up for recess. Obama's education secretary, Arne Duncan, is praising Los Angeles' move to link teacher promotions to a single score that allegedly captures the "value added" of each teacher in raising pupil test scores. The science for calculating these magical numbers remains hotly contested among scholars.

Sacramento has bowed to Washington pressure to spawn more charter schools, despite three national studies that now show no discernible benefits for children attending charter campuses relative to their peers in regular public schools.

So, it was a teachable moment when angry New York City parents - incensed by their children's collapsing scores - shouted down New York City schools chief Joel I. Klein, who then walked off the stage at a forum last month. New York state officials now admit that their not-so-standardized tests had been getting easier to pass as the city's ambitious reforms were kicking in, so they recalibrated the exams to make them more rigorous. After students sat for the new reading exams last spring, just 42 percent passed, down from 69 percent in 2009.

It's a lesson that policymakers are failing to learn: Trendy school reforms built on grand promises and loose evaluation can yield great political enthusiasm but slight benefit for students.

Dumbed-down remedies have come from earlier presidents. Ronald Reagan claimed that stiff market competition and vouchers would invigorate the schools. George W. Bush claimed that more intense testing and closing bad schools, just as New York City is doing, would turn around public education.

President Obama's story line is more compelling. First, set demanding national standards and a common benchmark for proficient student performance. Second, attract stronger college graduates to the teaching profession. Then, create strong incentives for schools and teachers to innovate.

But then the president's initiative splits into fragmented remedies rich in political symbols yet poorly backed by evidence. Obama again defended last month his leaning on the nation's governors to expand charter schools, independent educators who serve just 2 percent of all students nationwide.

Yes, we must devise fair ways of purging lousy teachers from the schools. But the National Academies of Science have warned policymakers that most districts lack sufficient data and statisticians lack solid methods for estimating a teacher's discrete impact on student learning, after taking into account the influence of confounding factors. Obama's desire to signal tough love for teachers trumps careful policy.

Simple diagnoses also distract from serious dialogue on what ails the schools. One-third of the nation's entering teachers leave the profession within five years, often fleeing dismal and uninventive schools. The president's rush to silver bullets will further repel our best teachers.

Obama has said little about rising levels of child poverty, beyond the helpful dose of security offered by health care reform. Family poverty remains the more potent driver of children's learning curves, based on a half century of research.

The president is right to crack down on weak teachers and experiment with inventive policies. But we need a focused agenda that enriches schools as stimulating places in which to work and that avoids disparate remedies that play to the gallery but fail to lift students.