A common criticism of the current wave of more or less open courses is that there is a high drop-out rate with sometimes only 10-20% of students completing the course. In the traditional education system this is seen as a sign of abject failure but should we apply the same principles in judging the impact of open education? Does it really matter who completes the course or not since the motivation for studying via MOOCs and suchlike is not to gain academic credits but simply to learn. If only part of the MOOC is relevant to your current interests you will study that part and then move on. This is not a case of dropping out but more like dipping into a good book to read the parts that interest you.