Managing New York City schools is proving to be a challenge for Mayor Michael Bloomberg, who took charge of the $12 billion a year system after a school-governance reform became law two years ago.

The mayor's "Children First" plan, which went into effect eight months ago, is, not surprisingly, controversial. Among other things, the plan provides for a uniform curriculum for most city schools and the quick removal of violent students from a school.

The idea behind the uniform curriculum, according to the mayor, is to redress the problems of a decentralized school system, which allowed a profusion of approaches--many unproven--to teaching reading, writing and math. Uniformity of teaching practices and curriculum, the mayor contends, means that students and teachers who must move from school to school no longer have to adjust to different teaching methods and new curricula. He sees a standardized approach to the three Rs as the best way to raise student performance in all subjects.

The United Federation of Teachers begs to differ. Randi Weingarten, president of the union, says a uniform curriculum doesn't allow for teacher flexibility or creativity in the classroom and keeps in place a hierarchical command-and-control system. Moreover, she says, the overall plan hasn't made schools any safer.

Even the mayor agrees on the last point. Although violent students were to be removed quickly, the city hadn't opened enough suspension centers to do so, creating delays of up to three weeks. "Blame me," the mayor said in December on his weekly radio program. "I wanted control. I got control, and I am going to do something about it."