Abstract: Large-scale open online learning environments continuously record learner activities: the 54 courses conducted by HarvardX and MITx in the 2013-2014 academic year had 1.1MM participants who recorded over a half a billion actions. Increasingly, online learning platforms also support A/B testing frameworks that allow for a variety of experimental designs. This combination of data recording and experimentation opens up excited new avenues for educational research. This talk will provide an overview of the various research strands currently underway at HarvardX, inspired by social psychology, behavioral economics, instructional design, computer science, computational social science, and other fields. I will argue for three important shifts in the future direction of online learning research: from studies of engagement to research on learning, from siloed investigations to institutional data-sharing, and from post-hoc observational studies to more sophisticated research designs. One aim of the talk is to introduce the Applied Statistics community to the data and research opportunities available through HarvardX, and to encourage more faculty and graduate students to begin new studies with these data and new collaborations with us.