People are generally pretty smart. Never criticise people for responding rationally to incentive schemes (even if they are not responding in the way you had hoped and intended). Incentive schemes are intended to drive changes to behaviour and if you are a senior manager and you are not getting the behaviours you want from the incentives you introduced, it is your fault for introducing incentives that do not align to your intent.
It’s worth checking (focus group, pilot schemes, dialogue, just thinking it through clearly) how others might respond to a proposed incentive scheme.
Consider alternative approaches: communicate the identity, axes of goodness, preferred alternative future, current targets and desired behaviours. Then reward people who contribute to success and demonstrate desired behaviours. If this cannot be done through a trusted system of management, then trying to do it by “objective personal measurement targets” is unlikely to deliver what you want.
“We are managers, so we have to measure something” is a common point of view (at least based on my experience) and leads to most of the ridiculous situations outlined by Deming (as described in the section “You can’t manage what you can’t measure” ) – although perhaps it would better be rendered as “you will only mis-manage that which you mis-measure”