Up until now, only a handful of studies have examined the impact of start times on academic outcomes for elementary and middle school students. These studies have struggled to definitively isolate the effects of start times or analyze actual changes in start times. However, one study conducted in a middle school district indicates that shifting to later start times can lead to higher test scores, especially among low-performing students.
New Insights from North Carolina
We contribute to the existing research on start times by conducting a series of studies in North Carolina. This includes analyzing an urban district that shifted many elementary school start times from 9:00 am to either 7:45 am or 8:30 am, as well as conducting statewide analyses of start times in elementary and middle schools. Our research utilizes eight years of administrative data and examines a wide range of outcomes, including sleep, attendance, suspensions, course grades, and test scores, for all students and specific subgroups. Importantly, we focus on schools that have actually made changes to their start times, rather than relying on variations in start times between different schools. As a whole, our studies provide the most comprehensive evidence to date regarding the relationship between start times and academic outcomes for younger students.
Key Finding 1: Earlier Start Times – Small and Varied Effects on Elementary School Students
In collaboration with an urban district in North Carolina, we surveyed 5th grade students throughout the district about their sleep patterns and perceptions of their start times. Comparing students attending elementary schools that begin at 9:00 am to those attending schools starting at 7:45 am, we found that the latter group reported getting 45 minutes less sleep per night. Additionally, those starting at 7:45 am were roughly 40% to 74% less likely to agree that their school started at the right time, compared to their peers. These findings align with previous research demonstrating a strong link between school start times and sleep patterns.
Although later start times are associated with increased sleep duration for elementary school students, the effects on academic outcomes are modest and mixed. We discovered that student absences slightly increased after elementary schools shifted to earlier start times, with some evidence suggesting larger increases among white students and those living in rural areas. Conversely, earlier start times were found to modestly improve math scores, particularly for economically disadvantaged students and students of color. Our analysis did not identify any significant impact of start times on elementary school reading scores or suspension rates.
Key Finding 2: Earlier Start Times – Negative Impact on Middle School Students
Earlier start times have consistently negative effects on middle school students. We observed an increase in student absences following a shift to earlier start times in middle schools. This effect was particularly pronounced among economically disadvantaged students, suggesting that some students and families struggle to adjust to an earlier commute. Furthermore, middle school students, especially boys, were less likely to be suspended after their school switched to a later start time. For example, a one-hour delay in start time resulted in middle school boys being 2.5 percentage points less likely to be suspended at any point during the school year. Start times did not predict course grades for middle school students.
We also found substantial evidence linking later start times to improved test scores among middle school students. A one-hour delay in middle school start times predicted math scores that were 8% higher, and reading scores that were 4% higher, in terms of a standard deviation. To put these results into perspective, the magnitude of these estimates exceeded the average effectiveness differences between first- and second-year teachers.
Implications for Decision-Making on Start Times
Our findings underscore several important considerations for state and local education officials. Similar to prior research conducted on high schools, our results demonstrate that later start times are beneficial for the academic outcomes of middle school students. Conversely, we found that earlier start times for elementary school students have relatively small and mixed effects – these include a slight increase in absences, but also a modest improvement in math test scores. These findings align with the biological changes in sleep patterns that occur during puberty, typically experienced by adolescents in middle school or towards the end of elementary school.
Overall, our results suggest that school districts should prioritize later start times for high schools and middle schools. Evidence indicates that elementary schools can adjust their start times earlier to accommodate these shifts without negatively impacting student outcomes.
More broadly, we believe that our findings emphasize the connection between adolescent health and educational outcomes. Initiatives aimed at improving student health, such as later start times, providing free school meals, and establishing school-based health clinics, can contribute to enhanced student engagement and achievement. This is particularly relevant in the aftermath of the COVID-19 pandemic, as districts and schools strive to support students in their social-emotional well-being and academic recovery.