Educators are still debating the merits of social promotion, more than 25 years after a national study said the decision to pass should be based on what students have learned rather than their age.

For decades, the education pendulum has swung back and forth between experts who say holding children back will lead to more dropouts and those who say it will foster academic mastery and future success.

The National Commission on Excellence in Education's 1983 study, "A Nation at Risk," concluded that grade placement "should be guided by the academic progress of students and their instructional needs, rather than by rigid adherence to age."

As of 2005, 18 states required students to pass a test for at least one grade to be promoted, said Kathy Christie, chief of staff at the Education Commission of the States, which collects education research.

Several large urban districts, including Chicago's and New York's, have gotten mixed results with policies that hold back failing students.

Academic research, while mixed, shows that holding children back in the lower grades does not help them catch up, Christie said.

Elaine Simon, codirector of the University of Pennsylvania's Urban Studies Program and a member of Research for Action, an education research organization in Philadelphia, agreed.

"They never really catch up," she said. "They are stigmatized, and that makes it worse."

Those findings have been challenged by the Manhattan Institute's Marcus Winters and Jay Greene, who looked at Florida's 2002 decision not to pass most third graders who scored below grade level on a statewide test. About 14 percent were held back in the first year.

The repeat third graders, who got extra help through summer school and worked with the best teachers in their second year, showed substantial improvement compared with those who moved on.

"The idea is that it will improve academic performance and put them back on a track to achieve," Winters said in an interview, calling the results "encouraging."

A study of a similar policy in Chicago, however, showed initial gains that were erased after two years.

James H. Lytle, a professor at Penn's Graduate School of Education, said that rather than focus on whether to hold students back, educators should examine what they need to do to reach students who are failing.

"The issue has become this tension between passing and not passing rather than the larger question of 'How are we going to help kids make it in the world?' " said Lytle, a former Philadelphia district administrator and Trenton superintendent.

The solution, said Christie, is to get prompt and high-quality help to students before they fall behind.

That's in keeping with the Rendell administration's proposal for state-developed high school end-of-course exams to identify struggling students. Those in danger of failing would get extra help.

A 2007 study showed the scope of the problem: About three-quarters of Philadelphia 11th graders had scored below grade level on either the math or reading state test in 2005, yet graduated the next year.

The Harrisburg proposal never got to the State Board of Education for a vote; it was derailed by opposition from school boards and politicians who said it would take away local control and rely too heavily on tests.