360 reviews with the team, OKRs, amount of input the person has on the team. How influential are they at helping get working code out the door. Agile shines a light on the fact that performance isn’t a quantative thing in knowledge work especially when embedded in a team. Its the same reason they stay away from sizing in hours, to get away from quantative judgements. Reviews should be how the person feels they could help the team better either by focusing inward and setting up skills they want to improve or outward by mentoring or being more active in the team.