The half-life of MOOC knowledge: a randomized trial evaluating knowledge retention and retrieval practice in MOOCs.

Retrieval practice has been established in the learning sciences as one of the most effective strategies to facilitate robust learning in traditional classroom contexts. The cognitive theory underpinning the states that actively recalling information is more effective than passively revisiting materials for storing information in long-term memory. We document the design, deployment, and evaluation of an Adaptive Retrieval Practice System (ARPS) in a MOOC. This push-based system leverages the testing effect to promote learner engagement and achievement by intelligently delivering quiz questions from prior course units to learners throughout the course. We conducted an experiment in which learners were randomized to receive ARPS in a MOOC to track their performance and behavior compared to a control group. In contrast to prior literature, we find no significant effect of retrieval practice in this MOOC environment. In the treatment condition, passing learners engaged more with ARPS but exhibited similar levels of knowledge retention as non-passing learners.