Do Differences in Schools' Instruction Time Explain International Achievement Gaps? Evidence from Developed and Developing Countries - Lavy, V (2015)
quasi-experiment; evidence grade B

New evidence on the importance of instruction time for student achievement on international assessments - Bietenbeck, J; Collins, M (2023)
replication; evidence grade B

Instruction time, Classroom Quality, and Academic Achievement - Rivkin, SG; Schiman, JC (2015)
quasi-experiment; evidence grade B

The Effect of Schooling on Cognitive Skills - Carlsson, M; Dahl, GB; Öckert, B; Rooth D-O (2015)
natural-experiment; evidence grade B

The Impact of Length of the School Year on Student Performance and Earnings: Evidence from the German Short School Years - Pischke J-S (2007)
natural-experiment; evidence grade B

Is four less than five? Effects of four-day school weeks on student achievement in Oregon - Thompson, PN (2021)
natural-experiment; evidence grade B

Do students benefit from longer school days? Regression discontinuity evidence from Florida's additional hour of literacy instruction - Figlio, DN; Holden, KL; Özek, U (2018)
quasi-experiment; evidence grade B

Increasing instruction time in school does increase learning - Andersen, SC; Humlum, MK; Nandrup, AB (2016)
rct; evidence grade A

The effectiveness of extended day programs: Evidence from a randomized field experiment in the Netherlands - Meyer, E; Van Klaveren, C (2013)
rct; evidence grade B

Evaluation of the Massachusetts Expanded Learning Time (ELT) Initiative: Final Study Findings - Checkoway, A; Gamse, B; Velez, M; Linkow, T (2013)
quasi-experiment; evidence grade C

Does lengthening the school day increase students’ academic achievement? Results from a natural experiment in Chile - Bellei, C (2009)
natural-experiment; evidence grade C

A systematic review and meta-analysis of the evidence on learning during the COVID-19 pandemic - Betthäuser, BA; Bach-Mortensen, AM; Engzell, P (2023)
meta-analysis; evidence grade B

The Effects of Summer Vacation on Achievement Test Scores: A Narrative and Meta-Analytic Review - Cooper, H; Nye, B; Charlton, K; Lindsay, J; Greathouse, S (1996)
meta-analysis; evidence grade D

Do Test Score Gaps Grow before, during, or between the School Years? Measurement Artifacts and What We Can Know in Spite of Them - von Hippel, PT; Hamrock, C (2019)
critique; evidence grade B

School’s Out: The Role of Summers in Understanding Achievement Disparities - Atteberry, A; McEachin, A (2021)
longitudinal; evidence grade B

When Does Inequality Grow? School Years, Summers, and Achievement Gaps - Kuhfeld, M; Condron, D; Downey, D (2019)
longitudinal; evidence grade B

The effects of increased learning time on student academic and nonacademic outcomes: Findings from a meta-analytic review - Kidron, Y; Lindsay, J (2014)
meta-analysis; evidence grade B

The Impact of Summer Programs on Student Mathematics Achievement: A Meta-Analysis - Lynch, K; An, L; Mancenido, Z (2023)
meta-analysis; evidence grade B

Learning from Summer: Effects of Voluntary Summer Learning Programs on Low-Income Urban Youth - Augustine, CH; McCombs, JS; Pane, JF; Schwartz, HL; Schweig, J; McEachin, A; Siler-Evans, K (2016)
rct; evidence grade A

Flaking Out: Student Absences and Snow Days as Disruptions of Instructional Time - Goodman, J (2014)
natural-experiment; evidence grade B

How Much Does Education Improve Intelligence? A Meta-Analysis - Ritchie, S. J.; Tucker-Drob, E. M. (2018)
meta-analysis; evidence grade B

Learning loss due to school closures during the COVID-19 pandemic - Engzell, P; Frey, A; Verhagen, MD (2021)
natural-experiment; evidence grade B

Intensive Math Instruction and Educational Attainment: Long-Run Impacts of Double-Dose Algebra (with the PNAS 12-year follow-up) - Cortes, K. E.; Goodman, J. S.; Nomi; T. (2015); Nomi, T.; Raudenbush, S. W.; Smith; J. J. (2021; PNAS) (2015)
natural-experiment; evidence grade B