With much fanfare four years ago, Mayor Bloomberg unveiled his plans to revamp the school system that he had been given control of six months earlier. Today, he is scrapping virtually all of those plans in what to me appears to be a “Hail Mary” pass to get back into a game that appears lost. If this were Iraq, call it a “surge.”

When the mayor was given control of the schools five years ago, it was because there was a sense of lack of control and direction coming out of the old Board of Education. There’d been a revolving door in the chancellor’s office during the old system’s final years. Alvarado, Quinones, Green, Fernandez, Cortines, Crew, Levy. Only one of these gentlemen left on his own accord, another died, and the others left in less than cordial circumstances.

Joel Klein, in contrast, is well into his fifth year as chancellor. The entire system has been changed to follow a model of his design. A “uniform curriculum” has been established. Procedures for, among other things, choosing principals and school budgeting have been altered. Dozens of schools have closed, replaced by hundreds of smaller schools, with new lines of command and control established under the Tweed Courthouse.

The results have been less than impressive. Test scores have increased in the lower grades, but in line with increases in the rest of New York, a state notorious for its inflated scores when compared with the nationally administered National Assessment of Educational Progress. Eighth-grade reading scores are just one point above where they were in 1999. The high-school graduation rate is said by the Education Department to be 58%. Outsiders from the national newspaper Education Week, which compiles graduation rates across the country, put the figure at only 43%.

Mr. Bloomberg’s shot at a legacy of fixing the schools is dwindling. If things were going well, yet another radical restructuring would not be necessary. So the scrapping of the Bloomberg/Klein plan unveiled just four years ago should be taken for what it is — an admission of failure. The problem is that there is no evidence that the schools can ever be fixed by changing the structure.

What needs to be changed is what goes on in the classroom, what our children learn, how they are taught. The new plan is based on four points. Most headlines focused on the mayor’s pledge to crack down on teacher tenure. What has taken him so long? Principals currently have three years, which can be extended to four, to determine whether a teacher is worthy of retention.

If poor teachers are being granted tenure, in a system that the mayor has controlled for nearly five years, the blame must fall squarely on Messrs. Bloomberg and Klein. I’m sure that Mr. Bloomberg, in his previous incarnation in the business world, needed a lot less time to evaluate his new employees.

Another change is a budgetary reform that would have “money follow the students,” a concept that some have either bemoaned or celebrated as “back door vouchers.” In reality it is nothing of the sort and would create a market disincentive for any school to retain more experienced and senior teachers. In essence, schools that establish a positive work environment would be punished.

Two brand new teachers would cost as much as a senior teacher. A school in chaos, where teachers leave in droves and are replaced by newcomers, would benefit financially. A school with a stable cadre of happy employees would be punished. The amount of funds assigned to schools is impacted largely by federal and state law, which require that certain allocations be used in specific ways, so there will never be a flat dollar amount per student.

The restructuring defies clear description. The line of responsibility that was the hallmark of the initial plan would be lost, as the system reverts to the 32 school districts that the chancellor and mayor once dismissed with contempt. How this scheme can improve student performance eludes me.

Missing from all this is what goes on in the classroom, an area that the mayor and chancellor should exercise more, not less control over. The tragedy of the first restructuring is that the original classroom mandates were the wrong ones, put in place by the chancellor’s first deputy, Diana Lam.

Teach at-risk children to read using scientifically validated phonics-based instruction, teach real math instead of the now discredited fuzzy approach, reintroduce methodical content instruction beginning in the lowest grades, and abandon failed bilingual programs. In other words, back to basics, which is what Mr. Bloomberg promised but has yet to deliver.