Must be a multiple of 3
Since workers can return an assignment or drop out, some "spare" participants will be created: the oTree session will have 2 times more participant objects than the number you enter here.
You can make more properties configurable by adding them to your session config in settings.py.
Public goods with punishment, roughly based on Fehr & Gaechter 2000.
NEO
Altruismus Skalen
Big 5 personality test