Back in January, my friend Bror Saxberg, chief learning officer of Kaplan, published an eye-popping blog about a meta-analysis that Kurt VanLehn published recently about nearly 100 well-constructed papers about computers used to tutor learners.

FORBES: How Machine-Based Tutoring Could Disrupt Human Tutors

It has been published in a number of papers, most recently in an edition of Water Resources Research.

BBC: Thames archive reveals long nitrate rise