Northwind +1
Also, I think there’s the aspect of direction/focus as well as level of effort which I think incentives can strengthen. It’s possible to have two extremely motivated colleagues, putting in equal levels of effort. However one is putting their efforts into less value-added activities. I’ve experienced bonus systems which address this, and which in effect replacing some supervision / line management resource, and hence being beneficial. When I’ve been on the receiving end of this, I appreciated the ‘breathing space’ that I had (no manager over my shoulder all the time), and the KPI & incentive system gave me clarity of objectives, and a sense of progress / job satisfaction that far outweighed the modest bonuses.