Conclusion: "The binding constraint appears to be engagement: realizing the promise of AI tutoring will require getting students to use it, not just giving them access."

My casual interpretation is that most kids didn't want to use the AI tutor. The authors estimate that time spent using the AI tutor is as effective as time spent studying without AI assistance, which is around one fourth as effective as studying with a real tutor. The real tutors are obviously quite expensive, comparatively.

So, if some kids do prefer studying with this AI tutor, that's as good as studying without it. Whichever approach gets them to put the study time in.

I have found this with my kids as well. I have an AI writing tutor that they use but only one of the two actually likes engaging with it. The other gets easily disengaged.

Some kids will be able to learn at a record pace with AI, others will need to be brought along in the usual ways via good teaching that fosters engagement.