Changing School Start Times: Impact on Student, Family, Teacher, and Community Health

Project Summary: 

The research team is conducting a multi-year, broad-based evaluation of how changing school start times impacts health and well-being for students in a diverse district in suburban Denver, Colorado. This study takes advantage of a natural experiment where the district changed school start times, with high school students starting at 8:20 a.m. (70 minutes later), middle school students starting at 8:50 a.m. (40-60 minutes later), and elementary schools starting at 8:00 a.m. (60 minutes earlier). The investigators are evaluating the impacts of the policy on the entire complex system that includes students in all grade levels, parents, school staff, and the greater community, utilizing quantitative data, contextual qualitative data, and community-based outcomes. The results of this project will be used to inform policymakers at the district, state, and national level about the community-wide impacts of changing school start times.


Health: Sleep routine and schedule; diet; exercise; caffeine use; depression; anxiety; nurse-documented student health visits for sleepiness, headaches, nutrition, and stomachaches; mental health utilization of support services; motor vehicle crash rates; and pedestrian safety

Other: School attendance, tardiness, and grades


The investigators are taking a longitudinal analytic approach to compare quantitative data from before and after the policy change occurred. Data are drawn from a number of different sources, including online surveys, district information, and community statistics.  Linear mixed models are used to fit continuous outcomes, while generalized linear mixed models are used for non-normal (i.e. count or binary) outcomes. The investigators are also collecting qualitative data through open-ended survey questions and focus groups to provide additional contextual data.

Principal Investigators: 

Lisa J. Meltzer, PhD

Amy Plog, PhD

Grant Start Date: 
February, 2018
Award Amount & Duration: 

$402,568 & 33 months