Employees give their shift preferences for the actual period on an intelligent web interface. The more you prefer a particular time, the higher score you give for it. Undesirable days are scored negative. The scores come from the incentive system monthly. If you are better at work you will have more scores. The more scores you have the more you can shape the roster according to your needs.

So it is a free of charge incentive system that is very much loved by agents.

The preference is not a must. It is fulfilled only if the algorithm can satisfy the conditions system. It counts mainly when the algorithm compares the employees during rostering. (Who wants this shift more?)