NEW YORK — Mayor Michael R. Bloomberg won control of this city's schools nearly four years ago and swiftly unleashed a dizzying string of reforms.
Bloomberg and his schools chancellor, former federal prosecutor Joel I. Klein, slashed administrative jobs, ordered uniform reading and math programs and hired parent coordinators for New York's 1,400 schools.
The pair converted warehouse-like high schools into smaller campuses and ended the practice of promoting failing students to the next grade. Their underlings even dictated how teacher bulletin boards should be designed.
But the top-to-bottom overhaul came with a cost: The mayor and his schools chief have alienated teachers, parents and administrators, leaving many in the nation's largest public school system feeling disenfranchised and afraid to challenge City Hall.
The changes in New York -- and the stresses they have exposed -- offer possible warnings to Los Angeles Mayor Antonio Villaraigosa as he weighs his own takeover of the Los Angeles public school system.
Bloomberg, a billionaire businessman, is unapologetic about his policies and his hardball style of governing the school system, which has 1.1 million students. For the first time in years, he said in a recent interview, New York's schools have a clear line of authority with a single public official accountable for results.
"I don't think any serious person would suggest that we should run this school district by committee or that we should have a referendum on every change," said Bloomberg, 64. "The public said we want a decision-maker to go in there and do it right. You can't please everybody."
Whether mayoral control has made a measurable difference in New York is a matter of debate.
The city's fourth-graders posted significant improvement on state reading and math tests last year, and Bloomberg plugged the gains in his successful reelection campaign last fall.
But critics point out that other New York cities, such as Rochester and Syracuse, made even more progress in reading test scores. Those skeptics also point to New York City's eighth-grade test scores, which dropped slightly last year compared with a year before.
Regardless of test scores, many who study urban school reform believe that mayoral involvement can be instrumental in efforts to improve schools. A mayor, so the theory goes, can mobilize financial and political support to tackle public health, immigration and other issues connected with schools. The potential danger comes when future mayors put other priorities ahead of education.
In New York, experts believe that mayoral control has allowed Bloomberg and Klein to push through their student retention policies, for example, because they faced no opposition from elected board members.
"They are able to crack the whip more than is common in most cities," said Jeffrey Henig, a political science professor at Columbia University's Teachers College who studies the politics of school reform. "They sometimes have gone in with a bit too much haughtiness ... and cut themselves off from parent groups and teacher groups who know a lot from years of experience at the street level."
The school systems in New York and Los Angeles have much in common, both politically and demographically. Both have strong teachers unions and disparate groups vying for influence over the schools.
L.A. Unified, with 727,000 students, is second in size only to New York City's system. African Americans and Latinos account for the vast majority of students in both systems, 72% in New York and 85% in Los Angeles.
Both have multibillion-dollar budgets that dwarf spending in many other major American cities. And the two systems are among their cities' largest employers, providing jobs to tens of thousands of teachers, principals, bus drivers, janitors and other workers.
If there is one issue on which Bloomberg and his critics agree, it's that New York's public schools were in disarray when the Legislature granted him control in 2002.
For more than two decades, the school system had been split into 32 community districts, each with its own superintendent and school board.
The chancellor of schools had little authority over these local school boards, which were created to decentralize power but devolved into nests of corruption and launching pads for those seeking higher office.
Sitting atop this structure were a central Board of Education, the chancellor and the mayor, who had no formal power over education but who controlled the district's multibillion-dollar budget and often clashed with educators over spending.
Bloomberg sought to streamline this system.
He secured new state legislation that replaced the central school board with a 13-member advisory panel; he appointed the majority.
The mayor also was allowed to name the chancellor, who until then had worked for the school board.
