Simple solution that gets close to the social truth: ask team members to rank everyone else. Average the rankings.
It works surprisingly well and for teams of up to 10 people or so differences in rankings are mostly noise.
That's not the worst thing to do but is game able the same way a lot of the proposed methods are. The developer who brings donuts to morning meetings is likely to score very high on this measure. Also given the diversity challenges a lot of teams have it's possible unconscious (or even overt) prejudices will affect scoring.
It's something to add to the toolbox, and a consistently low score for one person is a sure sign of trouble, but ithe does have some of the same shortcomings the other approaches do.
I would (and expect of my peers too) only value the donut-bringing as a minor strength compared to their technical skills and interactions with me. Which I think makes a little game-ifying ok: If someone wants to make a conscious effort to be the donut guy instead of the never-say-hi-in-the-hallway guy, they've earned a few points.
The amount of points to award is the tricky point, maybe it depends on company culture. How much value does the lovable team player bring, how much value does the awkward quietly-fix-anything person bring?
I've seen peer ranking work well for hiring when people in the team are strong and are motivated to hire even stronger ones.
It doesn't work at all when the team members are not so strong. They tend to value people who don't question "best practices" and don't take bold, unconventional positions. In essence, groupthink wins.
