Researchers have found that children attending schools for just four days in a week perform better in mathematics than those who attend a traditional five-day school week.
"What interested me about our results is they were completely opposite to what we anticipated," said Mary Beth Walker, dean of the Andrew Young School of Policy Studies at Georgia State University in the US.
The study compared fourth-grade reading and fifth-grade math test scores for students who participated in a four-day school week, versus those who attended a five-day school week.
The researchers found a four-day school week had a statistically significant impact on math scores for fifth-grade students, while reading scores were not affected.
The study suggests there is little evidence that moving to a four-day week compromises student academic achievement.
The researchers have speculated on why the shortened school week positively affected students but there are not enough data to draw definite conclusions.
"We thought the longer days might give teachers an opportunity to use different kinds of instructional processes," Walker said.
"We also speculated that a four-day school week lowered absenteeism, so students who had dentist's appointments or events might be able to put those off until Friday and not miss school. We thought there might be less teacher absenteeism," Walker noted.
"My own personal hypothesis is teachers liked it so much--they were so enthusiastic about the four-day week--they did a better job. There is some evidence in other labor studies that four-day work weeks enhance productivity," she said.
The study was published in the journal Education, Finance and Policy.