I don't think having an unregretted attrition rate 'target' is necessarily a bad thing, but *if* you are going to go down this sort of route, then the "hiring manager" and the "firing manager" should be working to competing objectives, and not colluding in this way. The hiring manager could, for example, be incentivised to meet a lower UAR rate than the firing manager, and the decision to fire should be made based on some sort of objective measure which is difficult to game without actually impacting productivity (Maybe a metric which is hard to predict by virtue of being complex, compound and nonobvious -- which sounds like a perfect fit for a neural network of some sort -- of course, this seems all perfectly horrendous and dystopian - neural networks trained to decide who to fire? ... creepy.)