Schools across the U.S. have sharply restricted student use of phones during the school day. We evaluate one type of restriction—lockable phone pouches—using nationwide data combining large-scale surveys, GPS pings, standardized test scores, and school administrative records, along with sales records from the largest pouch provider. Using a staggered difference-in-differences design, we find that pouch adoption substantially reduces phone use as measured by GPS pings and teacher reports. In the first year after adoption, disciplinary incidents increase and student subjective well-being falls, consistent with short-term disruption. However, effects on well-being become positive in later years and disciplinary effects fade. For academic achievement, average effects on test scores are consistently close to zero. High schools see modest positive effects, particularly in math, while middle schools see small negative effects. We find little evidence of effects on school attendance, self-reported classroom attention, or perceived online bullying.

In sum, it is fine to want to run a school that way, but do not expect huge educational gains, if any.  The evidence on this is accumulating, but many seem unable to accept the results.  In any case it is not worthy of a major moral crusade.

Here is the NBER working paper, with top-tier researchers involved I might add, namely .