Student engagement is widely considered to be a switch - students are either 'on' or 'off'.
Classmetrics turns engagement into a score: teachers receive an objective rating of their class' engagement at an individual and a group level. The data is completely scalable, so they can compare results against other classes in their school or across the world. The system geared towards preventing problems, encouraging empathy and boosting academic results.
The best part? The data is created by the students themselves and is automatically collated and analyzed in real time. All teachers need to do is set aside 2 or 3 minutes at the start of class.