One goal for massive open online courses is that the educational benefits they provide scale as a function of the number and diversity of learners interacting with the platforms, since an increasing amount of data is available about what interactions and content increase engagement and learning,...

In contrast to typical laboratory experiments, the everyday use of online educational resources by large populations and the prevalence of software infrastructure for A/B testing leads us to consider how platforms can embed in vivo experiments that do not merely support research, but ensure...