Completion rates is something that MOOC watchers on either side of the fence have been obsessed with from day one. In this blog post, Martin Weller publishes some data collected by OU researcher Katy Jordan on completion rates, in particular factors that influence them. Although a full paper is promised in due time, the preliminary results are already quite interesting. To mention a few, the median completion percentage is around 12%; the larger the enrollment (or the larger the number of active users), the lower the completion rate; the longer a course takes to complete, the lower the completion rate. Martin Weller then raises a few questions, tongue in cheek as the data are correlational only. However, it would indeed be nice to know if shorter MOOCs fare better in terms of completion, or if people get better at learning with MOOCs over time.