I recently attended a workshop on Lean Business, organised by Enterprise Ireland.
There were some very good presentations there where companies showed the gains they had made by implementing lean practices.
In the course of one presentation, the presenter was asked about bonus or rewards schemes. He answered by saying that he was not in favour of individual reward or bonus schemes. He could see some merit in organisation schemes but not in schemes where an individual is singled out.
It reminded me of this very powerful video which summarises some recent research on motivation.
Its worth looking at.