Soraka performance metric?

I always use damage healed, and damage taken, as well as how many times I died. If you took little damage, but died a lot, that means your positioning was terrible, and you likely got caught out and deleted in a second. If your damage taken is high and you died little, youre likely building too tanky, and trying to soak hits for your team, which as Soraka is a bad idea. Low damage taken and low deaths mean great positioning, but only if your kill participation is high. Low deaths and low kill participation just means youre too much of a coward and need to help the team more

So....you can go by KDA...assists/kills to deaths

Damage healed is a good metric...

It's all about them wards bro. You gotta place wards as a support and get rid of enemy vision.