This seems like the single worst way to measure this because by looking at chronological data you get all kinds of temporal effects. A better baseline would be

This seems like the single worst way to measure this because by looking at chronological data you get all kinds of temporal effects. A better baseline would be to look at the difference between pre-cell phone ban scores and post cell-hone ban scores compared to other districts where the cell phone ban didn't occur. I find it completely unremarkable that test scores went up post-COVID and feel it's very hard to tell what is causing what.