Expert Commentary

Time of day and student productivity in middle school and high school

2016 study in The Review of Economics and Statistics that examines whether adolescents have higher grades, test scores if their math and English classes are scheduled at the start of the school day.


Public school administrators are continually looking for ways to boost student achievement. In recent decades, some school districts have lengthened school days and others have experimented with school start and end times to try to improve student learning. In various parts of the country, high schools have begun implementing later start times, a response to complaints from parents and educators who say teenagers need more sleep and have trouble getting to class on time. In late 2014, the American Academy of Pediatrics took a stance on the issue, recommending that middle schools and high schools start classes at 8:30 a.m. or later to “align school schedules to the biological sleep rhythms of adolescents.”

Academic scholars have studied the relationship between time of day and student learning to better understand the opportune time for teaching core subjects such as reading and math or administering high-stakes standardized tests. A growing body of research examines the issue from multiple angles. A 2016 study published in PNAS, for example, suggests that students aged 8 to 15 years are more likely to do better on standardized exams in the morning because, over the course of a school day, children may experience cognitive fatigue. Meanwhile, a 2011 study led by scholars at the University of California, Davis indicates that college freshmen’s grades tend to be lower when they study certain subjects — chemistry and computer science, for instance — very early in the morning.

A 2016 study published in The Review of Economics and Statistics sought to determine whether scheduling math and English courses at the beginning of the day or at the end of the day would result in higher grades and test scores for adolescents. For the study, “How the Time of Day Affects Productivity: Evidence from School Schedules,” Nolan G. Pope of the University of Chicago analyzed the grade-point averages and standardized test scores of nearly 2 million students enrolled in grades 6 through 11 in the Los Angeles Unified School District. He examined data collected between 2003 and 2009, including scores from the math and English sections of the annual California Standards Test (CST). For the middle school students and high school students in the study sample, the school day typically started around 8 a.m. and ended around 3:10 p.m.

The study’s key findings include:

  • Students who had a math class during the first two periods of the school day earned higher scores on the CST math section than students who had math class during the last two periods of the day. The average math CST score of students who had math during periods 1 and 2 was 309.8. The average score of students who had math during periods 5 and 6 was 304.5. Students who had math class early in the day also had slightly higher grades in their math courses.
  • Students who had English during first or second period had slightly higher grades in the subject than students who had English class late in the day. There was no significant difference in English CST scores.
  • Advanced Placement (AP) courses — advanced-level courses that high school students can take for college credit — were almost three times more likely to be scheduled during the first or second period of the school day than during the last two periods of the day.

This study suggests that students tend to be more productive in the morning than they are in the afternoon, especially in math. While the author cannot say for certain why, he identifies three possible causes or contributing factors: changes in the quality of instruction over the course of the school day, changes in students’ learning ability during the school day and differences in student attendance at the start and end of the school day. The author states that “rearranging school schedules can lead to increased academic performance,” but notes there are constraints to how much school administrators can alter those schedules. One constraint is the supply of teachers at a given school who teach a particular subject.

Related research: A 2015 study published in Learning, Media and Technology, “Synchronizing Education to Adolescent Biology: ‘Let Teens Sleep, Start School Later,’” examines the consequences of an early school start time. A 2011 study in the American Economic Journal: Economic Policy, “A’s from Zzzz’s? The Causal Effect of School Start Time on the Academic Achievement of Adolescents,” looks at how starting the school day later influenced academic achievement among U.S. Air Force Academy students. A 2006 study in the Review of Educational Research, “An Analysis of Research on Block Scheduling,” offers a review of 58 empirical studies on high school block schedules, including their effect on student performance.


Keywords: education, high school, middle school, learning, adolescence, class schedule, school schedule, math, reading, academic achievement

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