Replication Data for: Non-unitary parties, government formation and Gamson's Law

Following the coalition literature highlighting intra-party politics (e.g., Laver 1999; Strøm 2003; Gianetti and Benoit 2009), I address the well-known “portfolio allocation paradox” (Warwick and Druckman 2006) by introducing a new model of government formation based on two main assumptions. First, no actor has a structural advantage in the negotiations leading to government formation. Second, all actors who can deprive the coalition of a majority (or other critical threshold size) must be included in the negotiations—not just parties. Whereas standard bargaining models are inconsistent with Gamson’s Law, the model proposed here implies that equilibrium portfolio allocations should be mostly Gamsonian but with a small-party bias, as the empirical literature has long found. Empirically, I show that my model outperforms the literature’s standard specification (due to Browne and Franklin 1973). Moreover, one of the model’s new predictions—that candidate-centered electoral rules should promote more Gamsonian portfolio allocations—is supported.

遵循聚焦党内政治的联合政府研究脉络（如Laver 1999、Strøm 2003、Gianetti与Benoit 2009），本文针对学界知名的「内阁职位分配悖论」（Warwick与Druckman 2006），提出基于两项核心假设的政府组建新模型。其一，在政府组建的谈判进程中，无任何行为体具备结构性优势；其二，所有能够剥夺联合政府多数席位（或其他关键临界规模）的行为体均需纳入谈判范畴，而非仅涵盖政党。尽管标准议价模型与加姆森法则（Gamson's Law）相悖，但本文提出的模型却表明，均衡内阁职位分配应整体符合加姆森法则，同时存在小党派偏向——这与经验研究文献的长期发现相符。实证层面，本文证明所提模型优于学界现有标准设定（源自Browne与Franklin 1973）。此外，该模型的一项全新预测——以候选人为中心的选举规则将推动更符合加姆森法则的内阁职位分配——得到了实证支持。