We create goals for an intended consequence. For example, we set a sales goal with the idea that we will achieve the sales goal and make the business successful.
However, every goal has unintended consequences as well. Managers should spend time trying to anticipate these unintended consequences.
A great example of an unintended consequence is the situation at Wells Fargo several years ago. Management set sales targets for products and based bonuses and reviews upon meeting those targets. The intended consequence is additional sales for the company. The unintended consequence was that people committed crimes and fraud to make the sales - fake applications, etc.
Managers can’t possibly defend against everything - if someone wants to cheat and game the system, they will. However, managers need to think about these things so they can be on the lookout for it.
With every goal you set - ask yourself “how can this cause damage and is there anything for which I should look?”