This is why you need to structure your review process around objectively verifiable info as much as possible. Have clear areas of responsibility for each individual, such that you can readily evaluate what they accomplished and how well it's working. They are responsible for a particular mission and set of objectives, and they either achieve them or they don't. This can't work without individual ownership, which is a…
Structuring the review around objectively verifiable data creates other problems. What if there's a developer on the team who delivers 1/3rd the features as everyone else, but they offer such effective mentorship that their five teammates deliver features 2x faster? If you design your review process around objectively verifiable data, then it's almost certain to undervalue a developer who's great at mentorship becaus…
I haven't really encountered this. Generally speaking people who can teach others to be much more productive like that are unsurprisingly themselves, more productive.
This fictional person would be better suited to a people management or coaching role as a individual contractor they only achieve a third of the average.