The shorter school week, which first emerged in a few rural areas decades ago, is now expanding into suburbs and smaller cities. At least 2,100 schools in half the states have embraced the three-day weekend mostly as an incentive to hire and keep teachers, prompting cheers of support from instructors, unions, and many families.  

Despite the growing popularity of the shorter week, some researchers and lawmakers are pushing back on the strategy. While its impact on teacher shortages appears to be mixed in different districts, its harmful effects on the academic growth of students – arguably the top priority of public education – is clear. Teams of researchers examining the program in a variety of states have come to a similar conclusion: The four-day week stymies learning in math and English when instructional time is reduced, as is often the case. 

The most authoritative multi-state study to date found that students have suffered small-to-medium negative effects, learning "significantly less" than they would have in a traditional five-day program, says co-author Emily Morton of the Center for Analysis of Longitudinal Data in Education Research.

The push for a shorter week comes at a troubling time for public schools. Many districts remain in a tough spot in the wake of the pandemic, suffering from increased teacher turnover as well as classrooms full of students who have recovered only a small portion of months and even years of lost learning. What's more, an unprecedented $190 billion in emergency federal aid ends in September, adding to the financial pressures on districts.

While superintendents see the four-day week as an inexpensive way to address the need for teachers, they also risk causing further harm to students. "It's a huge mistake to move to a four-day school week," said Matt Kraft of Brown University, who co-wrote a paper on the influence of class time on learning. "At this moment we need to maximize instructional time to support students' academic recovery, not reduce it."