Lots of great ideas have emerged in education in recent years, such as the idea of a flipped classroom, remote learning initiatives, project-based classrooms, etc. However, it's not clear to me to what extent these new methodologies are actually being tested for effectiveness. In classical mechanics, for example, the efficacy of new classroom techniques (such as TEAL) is often tested against a well-worn learning inventory via pre- and post-tests. Has such validation been conducted for edX classes, and have proper techniques been developed by people with expertise in performing such validation (i.e. the learning sciences community)? New ideas are fantastic, and anecdotal evidence/suggestions from community members is certainly valuable, but I do not want to see widespread changes in teaching techniques unless there is some quantitative evidence that they will actually lead to improvement for at least a set of students. I believe it is critical to develop metrics for gauging the effectiveness of new learning initiatives that are accessible to the community so that changes can be effectively evaluated.