Student performance improved, especially on the earliest midterms. Results were significant—average scores were about half a standard deviation higher than previous offerings. This is well above the long run average in both courses— this term was an outlier.
Most surprising is that students noted the policy in their evaluations of the course— about 25% mentioned it in their open ended comments. And everyone who talked about it enthusiastically endorsed it.
The students said the policy (1) encouraged them to focus, (2) helped them take better notes, (3) kept them engaged, and (4) increased their enjoyment of the course. I did not expect this at all.
I thought I would get much more pushback on this from students, and I didn’t think student outcomes would be so significant. Given these results, I’m very encouraged to continue with the policy.
As more universities (including @OhioState with their new @Apple program) roll out iPads and tablets to all students we need to think long and hard about whether and how this technology will be beneficial. It does works in some settings, it doesn’t work in others.
Policy here. (And my student evaluations were unchanged from previous offerings of the same courses.) 
