https://www.afterbabel.com/p/lancet-study-flaws?utm_source=post-email-title&publication_
In this post, we show why the recent Lancet study’s assertions that restrictive phone policies in schools yield no benefits are unfounded. For example, the phone-policies in the ‘permissive’ vs ‘restrictive’ schools did not differ very much, their measure of academic performance was crude, and their measures of screen time were unreliable.
A recent study published in The Lancet (Goodyear et al., 2025) has generated news headlines suggesting that restricting phone use in schools has no effect on the wellbeing or academic performance of students. This contradicts several previous studies that did find such benefits.
In this post, we lay out several flaws in the design and interpretation of the Lancet study, and several oddities in the data that we believe render its “no benefit” conclusion unjustified.
The authors of the study claimed to have
[E]valuated the impact of school phone policies by comparing outcomes in adolescents who attended schools that restrict and permit phone use.
The word “impact” implies the ability to discern causality. The authors then assert that,
[T]here is no evidence that restrictive school policies are associated with overall phone and social media use or better mental wellbeing in adolescents
and conclude that
[T]here is no evidence to support that restrictive school phone policies, in their current forms, have a beneficial effect on adolescents’ mental health and wellbeing or related outcomes, indicating that the intentions of these policies to improve adolescent health, wellbeing, and educational engagement are not realised.
The authors note that they do find substantial associations between time spent using phones or social media and worsened mental health and wellbeing, physical activity and sleep, and attainment and disruptive behavior:
[T]he negative associations found between increasing time spent on phones/social media and worsened mental health and wellbeing do provide evidence on the need to address phone and social media use in adolescents, and school policies should be developed as part of a more holistic approach.