A new University of Minnesota report takes a look at how many students repeat grades in school.
Researchers examined data from first through eighth grade classrooms from 2002 to 2009 in nearly half a million schools nationwide.
U of M sociology professor John Robert Warren, who co-authored the report, said the practice of holding students back is rare but important to monitor.
"Even if nationally only 4 percent of first-graders are held back," Warren said, "that's still 1 in 25, so that's basically one in everyone classroom across the country."
Warren said this was the first time grade retention had been studied this way nationwide.
"There's never been a way to compare states one to another with respect to how often kids are repeating grades," he said.
The report showed students in first grade are held back most often. Minnesota had one of the lowest rates in the nation, with only 1 percent of students held back.
Warren said he hoped other researchers use the study's methodology to better investigate the pros and cons of students repeating grades.
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