School start time delays and high school educational outcomes: Evidence from the START/LEARN study

Area of Science:

• Adolescent health
• Educational psychology
• Sleep science

Background:

• Adolescents require more sleep, but high school start times often conflict with their natural sleep-wake cycles.
• Later school start times are associated with extended sleep duration in adolescents.
• The impact of delayed high school start times on educational outcomes remains less understood.

Purpose of the Study:

• To evaluate the effects of delayed high school start times on adolescent educational outcomes.
• To assess changes in late arrivals, absences, behavior referrals, and GPA following a school start time delay.

Main Methods:

• Analysis of 2153 adolescents from a cohort study in the Minneapolis-St. Paul metropolitan area.
• Comparison of educational outcomes between schools with delayed start times and those with early start times.
• Difference-in-differences analysis of data from baseline (2015-2016) and two follow-up years (2016-2018).

Main Results:

• A 50-65 minute delay in school start times resulted in fewer late arrivals and absences.
• Schools with delayed start times showed a 14% lower probability of behavior referrals.
• Grade point average (GPA) increased by 0.07-0.17 in schools with delayed start times, with effects more pronounced in the second follow-up year.

Conclusions:

• Delaying high school start times is an effective intervention for improving adolescent academic performance.
• Later start times positively impact key educational metrics, including attendance and GPA.
• The findings support the implementation of later high school start times to enhance both student health and educational success.