An online learning system selects content for a learning session and opens a user interface to start the learning session on a plurality of devices. A mode of instruction is selected for the learning session. An activity to perform associated with the content is presented. Performance of the activity is monitored and a performance metric and/or a heterogeneity metric associated with a key performance indicator for the activity performed is generated. Responsive to determining that the performance metric and/or a heterogeneity metric is outside of the target range, the mode of instruction may be switched automatically.