Group size and matching protocol in contests

We investigate the effects of group size and matching protocol in Tullock contest experiments. In a 2 × 2 factorial design, we implement partner and random stranger-matching protocols in contests between two and between three players. Group size does not affect overall absolute bid levels, but the rate of overbidding is lower in two-player groups across matching protocols. Matching protocol does not affect bidding behaviour for three-player groups, but a partner matching reduces both the level and dispersion of bids in two-player groups. These results show the joint effect of group size and matching protocol and suggest that identifiability in repeated play facilitates tacit collusion.