We found banning mobile phones at school leads to an increase in student performance. Our results suggest that after schools banned mobile phones, test scores of students aged 16 increased by 6.4% of a standard deviation. This is equivalent to adding five days to the school year or an additional hour a week.
The effects were twice as large for low-achieving students, and we found no impact on high achieving students.
Our results suggest low-performing students are more likely to be distracted by the presence of mobile phones, while high performing students can focus with or without mobile phones.