Adapting the ELO rating system to competing subpopulations in a “man-hill”

Paraschool (the French leading e-learning company, with more than 250,000 registered students), wanted an intelligent software to guide students in their graph of pedagogic items. The very large number of students suggested to use students as artificial ants, leaving stigmergic information on the web-site graph to optimise pedagogical paths. The differences between artificial ants and students led to describe a new concurrent paradigm called “man-hill optimization”, where optimization emerges from the behaviour of humans exploring a web site. At this stage, the need of rating pedagogical items showed up in order to direct students towards items adapted to their level. A solution was found in the ELO [12] automatic rating process, that also provides (as a side-effect) a powerful audit system that can track syntactic and semantic problems in exercises. For an effective use, this paper shows how the ELO rating process has been modified to overcome the Deflation problem.