The Research

The four-day school week has been studied far more rigorously in the past five years than ever before. Below is a curated collection of peer-reviewed research, prioritizing studies published since 2021, organized by topic. Working papers and major reports are listed separately and clearly labeled. The short version: the four-day week's effects depend less on the calendar itself than on how much instructional time a district keeps.

Peer-Reviewed Journal Articles (2021-present)

Academic Achievement

Thompson, P. N. (2021). Is four less than five? Effects of four-day school weeks on student achievement in Oregon. Journal of Public Economics. https://doi.org/10.1016/j.jpubeco.2020.104308

Thompson, P. N., & Ward, J. (2022). Only a matter of time? The role of time in school on four-day school week achievement impacts. Economics of Education Review. https://www.sciencedirect.com/science/article/abs/pii/S0272775721001138

Morton, E., Thompson, P. N., & Kuhfeld, M. (2024). A multi-state, student-level analysis of the effects of the four-day school week on student achievement and growth. Economics of Education Review. https://www.sciencedirect.com/science/article/abs/pii/S0272775724000189

Thompson, P. N., Gunter, K., Schuna, J. M., & Tomayko, E. J. (2021). Are All Four-Day School Weeks Created Equal? A National Assessment of Four-Day School Week Policy Adoption and Implementation. Education Finance and Policy. https://direct.mit.edu/edfp/article/16/4/558/97130

Morton, E. (2021). Effects of Four-Day School Weeks on School Finance and Achievement: Evidence From Oklahoma. Educational Researcher. https://doi.org/10.3102/0013189X20948023

Cost & School Finance

Thompson, P. N. (2021). Does a Day Lost Equal Dollars Saved? The Effects of Four-Day School Weeks on School District Expenditures. National Tax Journal. https://doi.org/10.1086/712916

Student Health, Behavior & Community Safety

Morton, E. (2023). Effects of 4-Day School Weeks on Older Adolescents: Examining Impacts on Academic Achievement, Attendance, and Behavior in High School. Educational Evaluation and Policy Analysis. https://doi.org/10.3102/01623737221097420

Tomayko, E. J., et al. (2021). Impact of Reduced School Exposure on Adolescent Health Behaviors and Food Security: Evidence From 4-Day School Weeks. Journal of School Health. https://doi.org/10.1111/josh.13095

Najam, R., & Thompson, P. N. (2026). Impacts of the Four-Day School Week on Juvenile Crime. Journal of Policy Analysis and Management. https://doi.org/10.1002/pam.70101

Fischer, S., & Argyle, D. (2018). Juvenile crime and the four-day school week. Economics of Education Review. https://doi.org/10.1016/j.econedurev.2018.03.010

Note on the study above: This 2018 paper was the first to document a link between the four-day week and a roughly 20% rise in juvenile crime on the off day. That finding remained unusual in the literature until it was revisited at national scale by Najam and Thompson (2026). It is included here as a foundational exception to our 2021-forward standard.

Adoption & Community (Missouri)

Anglum, J. C., & Park, A. (2021). Keeping Up With the Joneses: District Adoption of the 4-Day School Week in Rural Missouri. AERA Open. https://doi.org/10.1177/23328584211002842

Working Papers & Major Reports (labeled)

Camp, A., Anglum, J. C., Koedel, C., Lee, S. W., & Nguyen, T. D. (2025). The Effects of the Four-Day School Week on Teacher Recruitment and Retention. CALDER Working Paper 320 (working paper - not yet peer-reviewed). https://caldercenter.org/publications/effects-four-day-school-week-teacher-recruitment-and-retention

Morton, E., & Dewil, E. (2024). Impacts of Four-Day School Weeks on Teacher Recruitment and Retention and Student Attendance: Evidence from Colorado. CALDER Working Paper 307 (working paper - not yet peer-reviewed). https://caldercenter.org/publications/impacts-four-day-school-weeks-teacher-recruitment-and-retention-and-student-attendance

RAND Corporation (2021). Does Four Equal Five? Implementation and Outcomes of the Four-Day School Week. Research Report RR-A373-1. https://www.rand.org/pubs/research_reports/RRA373-1.html

Grant, S., et al. (2025). The Four-Day School Week at K-12 Schools in the United States: A Scoping Review of Empirical Research Evidence. Educational Evaluation and Policy Analysis (peer-reviewed review). https://doi.org/10.3102/01623737251362865

HEDCO Institute - Four-Day School Week Research Database (interactive evidence map of 100+ studies). https://hedcoinstitute.uoregon.edu/dashboards/four-day-school-week-research-database

A note on the evidence: the strongest recent studies of teacher recruitment and retention are still working papers, so the peer-reviewed base for that specific question is thinner than it is for student achievement. For our own team's peer-reviewed studies, see the Dr. Turner's Research page.