Kindergartners who are already academically strong at the beginning of a school year appear to learn even more during each day spent in school than their classmates who start the year behind.
That’s acording to a new analysis from researchers at American University and Rutgers University—Camden, and it implies that adding instructional days for all students may actually result in increasing gaps in academic performance.
Seth Gershenson, an assistant professor in the Department of Public Administration & Policy at American University, describes the findings on the Brookings Institution’s Brown Center Chalkboard site, which links to the original discussion paper.
Gershenson and his colleague Michael S. Hayes used information from the National Center for Education Statistics’ Early-Childhood Longitudinal Study. Students in that study took tests at the beginning and toward the end of the school year, but precisely how many days into the school year the second test was administered varied by school.
In 2010, a separate group of researchers used that variation to determine how days spent in school affected achievementThey found that on average, students who had been exposed to more days of school before the test performed better than peers who took tests earlier in the year.
Gershenson and Hayes wondered, however, if students were uniformly affected by the days.
“Generally, policymakers, analysts, and practitioners spend a lot of time looking at how interventions affect things on average,” Gershenson said. “But the effects of interventions are not constant for everybody.”
In the case of instructional days, it turned out that students who already scored well on the tests saw their scores improve significantly more than students who hadn’t done well at the beginning of the year.
There was no difference based on students’ socioeconomic or demographic background.
“It forces you to think carefully about what the prime objective is,” he said. “If you’re trying to raise achievement across the board, or trying to raise average achievement, that’s one thing. But that doesn’t necessarily mean it’s closing achievement gaps or improving the achievement of the population you’re most concerned about or interested in serving.”
Gershenson pointed out that all students were positively impacted by adding classroom time, but that higher-scoring students were simply benefiting more.
“The effect is always positive, it’s just that it’s bigger for some kids than others,” he said. “The reason that might be concerning is that it’s not the case that the biggest effects are for low-achieving kids.”
Interestingly, he said, students in the middle-high range saw even more gains than the students whose scores were strongest at the beginning of the year. He said this might imply that especially in kindergarten, when teachers have less previous knowledge about their students, teachers are targeting instruction to the average student rather than high-flyers or those who come into school behind.
One of the implications for those interested in helping the lowest-scoring students catch up to their peers might be that those students should receive more instructional time than their peers, he said. But, he said, any extra time should be spent in high-quality programs. “A lot of summer school programs aren’t necessarily effective,” he said.
A version of this news article first appeared in the Curriculum Matters blog.