Each additional hour of homework is associated with about 0.335 fewer hours of nightly sleep, and electronic device use is also negatively associated¶

Claim · All claims
Evidence · 1 study · associational r2 · q2
Currency · newest study 2025 · not yet checked against its sources · not reviewed by a person

Subclaims¶

q2 i? Homework time and electronic device use both show significant negative associations with sleep duration in OLS regression. → Wang 2025

Evidence¶

Wang 2025¶

Wang, M., Chen, Z., Han, N., & Yao, H. (2025). Sleep duration and subject-specific academic performance among adolescents in China. npj Science of Learning. https://doi.org/10.1038/s41539-025-00361-y

q2 · i? · associational · r2

Regression predicting sleep duration (Table 6): homework time −0.335, device use −0.118, both p < 0.001; jointly explaining R² = 0.132 in Model 3. The article notes homework plays a more substantial role than screen time.

"the coefficient for homework time was -0.335 (p < 0.001), indicating that each additional hour spent on homework was associated with a reduction of ~0.335 h in average sleep duration. The coefficient for electronic device use was -0.118 ( p < 0.001)"

Discussion¶

Learner Variables¶

• Sleep — outcome: instruction changes it

Related Claims¶

• Older adolescents show high night-to-night variability in free-living sleep duration, which may obscure sleep-cognition associations — related
• Sleep duration shows an inverted U-shaped association with academic performance in all five subjects, with a peak around 8 hours of nightly sleep — related
• Short sleep duration (<9 hours) at follow-up is associated with impaired academic achievement, while baseline sleep duration did not significantly predict later school performance — related
• Optimal sleep duration varies by subject: about 8–9 hours for mathematics and 7–8 hours for Chinese, English, science, and arts — related