Adolescents attending schools with restrictive, compared to permissive policies had lower phone (adjusted mean difference −0.67 h, 95% CI −0.92 to −0.43, p = 0.00024) and social media time (adjusted mean difference −0.54 h, 95% CI −0.74 to −0.36, p = 0.00018) during school time, but there was no evidence for differences when comparing usage time on weekdays or weekends.
That means they use the word “overall” to mean “out of school” in a study about school rules. Bravo.
The correct wording would be: