A big part of performance is, this is our culture, these are our values. Are you acting in concert with those? Because so often a person's contribution can't be easily measure but in terms of numerical ways. The question is, do you contribute? Do help? Do you work hard? Whatever those values are and are you making a difference? Even if you can't precisely measure that, that's not the point of this.
The concept of dignity in work is at the heart of organizational health, but it's not always as simple as it's made out to be. Dignity requires an emphasis on performance as well as humanity, but too often, companies focus on one at the expense of the other.