NEW YORK — Federally mandated public afterschool tutoring isn't always reaching the kids it's intended to help, new research suggests — and when it does, it doesn't always help as much as it could.

Findings from three cities presented here this week before the American Educational Research Association support previous research on the free tutoring that schools must offer under the No Child Left Behind law if math and reading levels don't rise for three years.

But new data from Los Angeles, Pittsburgh and Milwaukee find that few kids take up the offer. In Milwaukee, 90 percent of students who registered in 2003 attended sessions. By 2006, only 34 percent did.

In Milwaukee, researchers found no rise in scores. One reason, said Patricia Burch of the University of Wisconsin-Madison, could be that in many sessions tutors used "uninspired practices," such as handing out worksheets. Researchers in Los Angeles found similar results, though kids tutored for several years did better; in Pittsburgh, tutors got better results grouping kids by achievement level rather than grade level.

Charles Barone, who analyzed the findings for the Citizens' Commission on Civil Rights, said some of the programs "are terrible and should be terminated." But, he said, others are working and should be supported.

Barone, a former congressional staffer who helped write No Child Left Behind, added, "It's kind of a high bar for an afterschool program to have to improve academic achievement."

He noted that a Clinton-era program was lauded for keeping kids safe and occupied afterschool.

"I'd say this is a higher bar than what we've previously had for afterschool," he said.