Even the process of labeling some things as objective and others as subjective is up for debate. Everyone wants to claim their metrics are objective while everyone else's are subjective. I know you're hinting at "scientific" or "technocratic" approaches, but it's important to also understand how even the process of selecting objective measures can be polluted with subjectivity. I almost want to claim there's no escaping the subjectivity trap, but maybe I'm being too pessimistic.