Group size and decision rules in legislative bargaining

Abstract

We conduct experiments to investigate the effects of different majority requirements on bargaining outcomes in small and large groups. In particular, we use a Baron-Ferejohn protocol and investigate the effects of decision rules on delay (number of bargaining rounds needed to reach agreement) and measures of "fairness" (inclusiveness of coalitions, equality of the distribution within a coalition). We find that larger groups and unanimity rule are associated with significantly larger decision making costs in the sense that first round proposals more often fail, leading to more costly delay. The higher rate of failure under unanimity rule and in large groups is a combination of three facts: (1) in these conditions, a larger number of individuals must agree, (2) an important fraction of individuals reject offers below the equal share, and (3) proposers demand more (relative to the equal share) in large groups.

The Determinants of Multilateral Bargaining: A Comprehensive Analysis of Baron and Ferejohn Majoritarian Bargaining Experiments

“…The results reported in Table 6 and Figure 2 provide some evidence that an increase in group size, from 3 to 7 members (p = 0.069), may negatively affect the probability of a round-one agreement. This result is in line with the findings reported by Miller and Vanberg (2015) of higher rejection rates in groups of 7 compared to groups of 3. However, it should be noted that the evidence is not too strong (noisy estimates for group size 7 due to the small sample size for these groups).…”

Promises in group decision making

“…To focus on promises, we adopt the unanimity rule for intra-group decisions and exclude any other form of formal or informal communication within or between groups. We also compare different procedures of collective choice to verify the robustness of intra-group agreement with respect to factors that are relevant in bargaining modeling (Banks and Duggan, 2000;Miller and Vanberg, 2015;Song 2009).…”

Legislative bargaining with heterogeneous disagreement values: Theory and experiments

“…In a no-delay equilibrium, the proposer offers z i to q − 1 other players (the ones with the q − 1 lowest values of z i ) and 0 to the remaining players. 24 We are not (yet) claiming that the no-delay equilibrium is unique, just that other no-delay equilibria would lead to different values of L, M and H. 25 It is a known feature of legislative bargaining models that a given vector of equilibrium expected payoffs may be supported by several strategy combinations (see e.g. Eraslan and McLennan, 2013).…”