Conditions on the jury for the natural implementation of the deserving winner of a contest

A jury has to choose the winner of a contest. There exists a deserving winner, whose identity is common knowledge among the jurors, but not known by the planner. Jurors may be biased in favor (friend) or against (enemy) some contestants. We study conditions on the confi?guration of the jury so that it is possible to implement the deserving winner in Nash equilibrium when we restrict ourselves to mechanisms satisfying two conditions: (1) each juror only has to announce a contestant, and (2) announcing the deserving winner is an equilibrium. We call this notion natural implementation. We show that, in order to naturally implement the deserving winner, the planner needs to know a number of jurors with friends or a number of jurors with enemies. Speci?cally, the number of jurors with friends that the planner needs to know to naturally implement the deserving winner is less than the number of jurors with enemies that the planner would need to know for it.