Despite a century of research, educators continue to argue over whether it helps or hurts students to hold them back when they perform below grade level.

A recent panel sponsored by the Center on Children and Families at Brookings Institution explored the retention vs. social promotion divide. On the side of retention — at least as part of a comprehensive reform strategy — was Harvard professor and Mitt Romney campaign education adviser Martin R. West, who reviewed the research on social promotion and grade retention and the Florida results for a Brookings policy brief.

Since 2003, Florida has required that third graders scoring at the lowest level on state reading tests be held back and given intense remediation.

Compared with similar students who were not retained, the retained kids were 11 percentage points less likely to be retained one year after they were initially held back and roughly 4 percentage points less likely to be retained in each of the following three years, according to West. As a result, students retained in third grade after five years are only 0.7 grade levels behind their peers who were immediately promoted to grade four.

While West agrees that the short-term benefits of retention diminish over time, “the retained students continue to perform markedly better than their promoted peers when tested at the same grade level and, assuming they are as likely to graduate high school, stand to benefit from an additional year of instruction. These factors may increase the likelihood of enduring benefits.”

But researcher and fellow panelist Shane Jimerson of the University of California Santa Barbara opposed retention in any form, explaining, “Among over 1,000 analysis of achievement and adjustment outcomes during the past 100 years, there are few that reveal significant positive effects associated with grade retention. Whereas short-term gains, for instance, during the repeated year and possibly the following year, are occasionally documented, the long-term effects through middle school and high school are either neutral and/or deleterious. And grade retention has emerged as one of the most powerful predictors of high school dropout.”

Jimerson said Florida introduced many interventions along with retention and it has not yet been shown — which all panelists agreed — whether these other elements may have been the causes of the state’s improved reading performance.

He noted that the other elements — summer school, putting retained students with high-performing teachers, an intense reading focus in the classroom, progress monitoring, parent engagement — have been proven to be effective.

“Whereas many of the other components in the Florida program are empirically based and laudable, retention is not,” he said.

Misgivings over retention have not ended the practice.

New data from U.S. Department of Education’s Office of Civil Rights shows that 2.3 percent of all students in 7,000 districts — which represent 85 percent of all children in U.S. public schools — were retained at the close of the 2009-10 school year.

Only 1 percent of those students were in elementary or middle school, and most repeated kindergarten or the first grade. The federal data found retention highest among black and Hispanic students.

Retaining a student is costly. With the national per-pupil spending average at $10,700, the price tag for retaining 2.3 percent of the 50 million public school students exceeds $12 billion a year. That amount excludes the costs of remedial services for students or their delayed earnings from entering the job market a year later.

But panelist Mary Laura Bragg, who helped craft and put Florida’s prevention/retention policy into practice under then-Gov. Jeb Bush and now works with his nonprofit Foundation for Excellence in Education, said the goal should not be retention.

The intent of Florida’s policy was to prod schools into improving their k-2 classes so retention was not necessary in third grade, she said.

A former high school history teacher, Bragg said, “I have seen the vacant stare of a 10th grader when the student is asked to read out loud or discuss something they read. I’ve been a recipient of victims of social promotion.”

In the four years she directed Florida’s policy, Bragg said she witnessed a “sea change in reading instruction in grades k-3. It’s a shame that the threat of retention is what got elementary schools doing what their primary focus is — to teach kids how to read.”