A study published in the Journal of Political Economy, one of the world's top economics journals, provides the first causal evidence that improving sleep can directly enhance academic performance. In a large-scale field experiment involving more than 1,100 university students in the United States, researchers Osea Giuntella (University of Pittsburgh), Silvia Saccardo (Carnegie Mellon University), and Sally Sadoff (UC San Diego) tested whether small monetary incentives could help students build better sleep habits, and whether those habits would translate into higher grades.
Students Were Severely Sleep-Deprived
At baseline, students slept an average of 6.6 hours per night. Only 43% reached the seven-hour target the study set for weeknights. More than 85% of participants failed to get seven hours of sleep on at least one school night each week. About half of students went to bed after 1:00 a.m. on average, and one in four went to bed after 2:00 a.m.
An Ambitious, Technology-Enabled Design
The study combined objective sleep tracking using smart wristbands with a custom-built smartphone app that delivered bedtime reminders, real-time feedback, and immediate digital payments. The app allowed the researchers to monitor engagement, track syncing behavior, and test how different combinations of cues, feedback, and incentives affected both short-term sleep and longer-term habits. In addition, participants completed weekly surveys on time use, mental health, and cognitive performance, including tests of creativity and quantitative problem-solving. This rich dataset allowed the researchers to identify how changes in sleep patterns affected students' daily routines, stress, and academic productivity.
"This was one of the most comprehensive behavioral field experiments ever conducted on sleep," said Giuntella. "By integrating wearable technology, real-time incentives, and psychological measures, we were able to observe both the formation of sleep habits and their educational impact."
Small Rewards, Longer Sleep
Participants were randomly assigned to receive personalized bedtime reminders, morning feedback, and small cash rewards (about $4.75 per night) for meeting a seven-hour sleep goal, verified through the sleep-tracking wristbands. The intervention increased the share of nights with seven or more hours of sleep by 26%, adding about 19 minutes of weeknight sleep. Students in the incentive group also earned 0.075-0.089 higher grade points that semester, a 0.10-0.11 standard deviation improvement.
"Our results show that helping students sleep more, and sleep better, can boost academic performance just as effectively as traditional academic interventions," said Giuntella.
Freshmen and STEM Students Benefited Most
The effects on sleep and academic performance were driven primarily by freshmen, a population suddenly out of their parents' control, and for the first time in charge of managing their time. The benefits were strongest in STEM courses, and in classes held around midday, suggesting that well-rested students perform better in the most cognitively demanding contexts.
Better Routines, and What Didn't Change
The program helped students build more regular sleep schedules and cut back on nighttime screen use, including time spent watching videos or browsing the internet. Total study time remained unchanged, but students shifted some studying from late evening to morning hours. The intervention did not significantly change average physical activity or end-of-semester mental health scores. Participants did report feeling better able to cope with stress during the treatment period, which is consistent with improved sleep quality and regularity.
What Stayed After the Payments Stopped
The more telling number arrived after the money stopped. The 19 extra minutes a night that cash had bought settled into lasting gains of about 8 minutes per night, alongside steadier bedtimes and less late-night screen time. The payments ran for part of a semester. A piece of the routine stayed on after them.