Abstract
Before group members individually decide their e§orts in a contest, groups are allowed to make some concessions to their opponent by chosing a less controversial policy to lobby for. When valuations over the set of policies follow a linear function, we show that concessions are never proÖtable when the contest success function is homogeneous of degree zero but they are when it is of di§erence form. Surprinsingly, concessions are detrimental for the members of the group that does not make them. Comparing this situation with another where e§orts are decided collectively at a group level allows us to remark free-riding as the key cause of this damage.