Reich & Ruipérez-Valiente’s 2019 Sciencestudy tracked every MIT & Harvard course on edX from 2012 to 2018 — 5.63M learners across 12.67M registrations. Completion fell from roughly 6% in 2014–15 to about 3% by 2017–18, and hasn’t budged since.
It’s not a content problem — Coursera’s catalog is excellent. It’s a formatproblem: video lectures don’t generate engagement, and quizzes graded once at the end of a module don’t generate retention. The drop-off cliff is by week 2.
Bruner inverts the format. The session is a conversation. The “quiz” is continuous — every concept is reviewed when you’d be about to forget it. The capstone keeps you anchored to a thing you actually want.