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21 November 2019

The School of Economics and Finance invites you to attend a seminar where Dr Aaron Kamm from the University of Melbourne will present on "What Causes Gamson’s Law? Experimental Evidence on Coalitional Bargaining and Commitment".


One of the most robust findings in the literature on coalition formation is that government portfolios are allocated proportionally to the seat shares of coalition parties (Gamson’s Law). Surprisingly, standard bargaining models are not able to reproduce this pattern because in these models outcomes are a function of real and not nominal bargaining weights. This begs the question why Gamson’s Law is empirically so robust. In this paper we consider two possible mechanisms and test them in a laboratory experiment. First, we conjecture that the proportionality might be due to bargaining parties respecting the voters’ preferences expressed in the vote shares. Second, we propose a different structure of the bargaining process where parties first choose with whom to form a coalition before deciding how to split the office rents. This model generates the proportionality predicted by Gamson’s Law. The experimental results provide no support for the first mechanism since behaviour is not affected by bargaining weights being purely abstract. In contrast, we find very strong support for the second mechanism both in terms of comparative statics and point predictions. Overall, our analysis strongly suggest that Gamson’s Law might be caused by parties first forming coalitions before bargaining over portfolios.

Everyone is welcome to attend.

For more information please see Dr Aaron Kamm's website.


21 November 2019 - 21 November 2019
11:00am - 12:30pm
Gardens Point Campus, Z Block, Level 8
GP - Z808
Free to attend
QUT School of Economics and Finance
Dr Dipa Sarkar
07 3138 6683
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