The question of whether or not something works is a basic one to ask when investing time and money in changing practice and in using new technologies. For learning analytics, the moral dimension adds a certain imperative, although there is much that we do by tradition in teaching and learning in spite of questions about efficacy.
http://blogs.cetis.ac.uk/adam/2014/10/17/on-the-question-of-validity-in-learning-analytics/