Regardless, defined performance metrics are better than none at all. You have to create the formality around performance evaluation or else you end up with those who understand the informal rules outperforming those who don’t simply because they grew up in a certain environment. I don’t think anyone would claim that’s fair, but that’s how the “meritocracy” works when you don’t define these things formally.
On the flip side, when you do define these things formally, you end up with those who can and will game the formal rules more effectively outperforming those who don't. This isn't fair either, and there are probably all sorts of biases in who is willing and able to game such metrics (for example, I have seen men game them more often).
Evaluating performance is tough. Evaluating performance without greatly distorting incentives is much tougher. I agree fairness should be a consideration, but it is not the primary purpose of a business.
By not defining them, you leave the priorities of the business up to what amounts to a popularity contest with each manager. Raises and promotions thus get handed out to the people who are most likable.
Senior executives (usually VP and above) at major companies typically sign contracts explicitly outlining their goals for the next 12-24 months. They are incentivized or fired based on meeting those goals. And it’s the executives who demand this, not the companies.
Point being, if the executives are demanding clear performance goals for themselves, it’s probably good practice. Managers typically are not responsive to demands from below, so guess where the mandate has to come from.
