The percentage of students held back a grade fell by nearly half from the 2004-2005 school year to 2009-2010, with the sharpest drops among boys and students of color, according to a study published Thursday in the journal Educational Researcher.
The retention rate -- the percentage of students held back -- peaked in 2004 and has steadily declined since.
Among black students, the retention rate dropped by more than half from 2004 to 2009, from 4.9 percent to 2 percent.
The study is one of the first to collect national data on student retention. Some states report their own information, but the new study used data from the census, which has collected information indicating whether a child was held back since 1995.
The study didn't explain the decline. Lead researcher John Robert Warren speculated one factor may be the Statewide Longitudinal Data System that allows states to share data, which may have shown school administrators the rate of students held back and "how disparate they are across ethnic and class groups."
"Nothing in this study should suggest that [the decrease in retention rates] is a good or a bad thing," Warren told The Huffington Post.
Warren said he doesn't believe the recession or No Child Left Behind affected the drop in the percentage of black students who were held back. The recession may have plausibly affected rates as it costs more for a school to keep a student another year, but Warren said the downward trend began before the economic crisis. No Child Left Behind, on the other hand, would have increased retention rates, if anything, as students would be held back rather than be sent unprepared to a testing grade, he said. This idea extends to state exams that require students to be held back if they fail, such as Ohio's.
The drop in the percentage of students being held back came as 15 states and the District of Columbia adopted policies that require students to pass an exam to move beyond third grade. President Barack Obama has spoken out against social promotion -- moving a child to the next grade just to stay with same-age classmates.
"If you survey people, they’ll say social promotion is wrong, but when the rubber meets the road a lot of staff members are reluctant" to hold back students, said Arzie Galvez, a Los Angeles Unified School District administrative coordinator.