Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
A group of n≥2 experts has to pick one winner from a group of m≥2 candidates. Different experts may have different judgments about who the best candidate is. A social choice rule (SCR) is q-supermajoritarian (with q≥n2+1) if, whenever a candidate is judged as best by at least q experts, that candidate is considered to be the deserving winner. Experts may be biased and their preferences are not necessarily aligned with their judgments. Then, the social planner has to design a mechanism that implements the SCR. We show that implementability of a q-supermajoritarian SCR in an ordinal equilibrium concept requires the group of experts to satisfy a condition of impartiality that depends on q (the higher q, the weaker the condition).