[论文解读] The Role of Race, Ethnicity, and Gender in the Congressional Cosponsorship Network

Alison Craig, Skyler Cranmer+3 more|arXiv (Cornell University)|Dec 18, 2015

Electoral Systems and Political Participation参考文献 37被引用 11

一句话总结

本研究运用时间指数随机图模型分析1981–2004年美国众议院共sponsor网络，发现由于种族同群混合，非裔和拉美裔议员面临相对劣势，但这一劣势在选举压力下得以缓解：代表非裔/拉美裔占多数选区的议员更有可能共sponsor由种族/族裔少数群体同事发起的法案。女性议员未面临类似劣势，表明基于性别的同群效应较弱。

ABSTRACT

Previous research indicates that race, ethnicity, and gender influence legislative behavior in important ways. The bulk of this research, however, focuses on the way these characteristics shape an individual legislator's behavior, making it less clear how they account for relationships between legislators. We study the cosponsorship process in order to understand the race and gender based dynamics underlying the relational component of representation. Using a temporal exponential random graph model, we examine the U.S. House cosponsorship network from 1981 through 2004. We find that Black and Latino members of Congress are at a comparative disadvantage as a result of race-based assortative mixing in the cosponsorship process, yet this disadvantage is mitigated by the electoral pressures that all members face. Members representing districts with significant racial and ethnic minority populations are more likely to support their minority colleagues. We also find that women members do not appear to face a similar disadvantage as a result of their minority status. We argue that these race and gender dynamics in the cosponsorship network are the result of both the inherent tendency towards intra-group homophily in social networks and the electoral connection, which is manifested here as members supporting minority colleagues to broaden their own electoral base of support among minority constituencies.

研究动机与目标

• 探究种族、族裔与性别如何塑造美国众议院共sponsor网络中的关系动态。
• 评估少数族裔议员是否因同群效应而在建立立法联盟时面临结构性劣势。
• 考察选举压力（特别是少数族裔选民间接代表）在调节此类劣势中的作用。
• 比较种族/族裔与性别维度在立法合作中的同群效应程度。
• 评估重新划分选区与非裔/拉美裔占多数选区对国会议员跨群体支持的影响。

提出的方法

• 采用时间指数随机图模型（tergm）分析1981至2004年美国众议院共sponsor网络。
• 引入随时间变化的网络效应，以建模共sponsor关系随时间的演变。
• 纳入节点属性（如种族、族裔与性别）以检验关系形成中的同群效应。
• 将选区层面的种族与族裔构成作为关键协变量，评估选举压力对共sponsor行为的影响。
• 通过按分位数分组的共sponsor概率分析，量化选区少数族裔人口比例对共sponsor行为的影响。
• 控制立法意识形态、资历与政党归属，以隔离身份与选区构成的影响。

实验结果

研究问题

• RQ1 在排除其他因素后，种族与族裔身份在多大程度上塑造了美国众议院的共sponsor关系？
• RQ2 议员所属选区的种族或族裔构成在多大程度上影响其共sponsor少数族裔同事发起法案的可能性？
• RQ3 共sponsor行为中是否存在显著的性别同群效应？其与基于种族的模式相比如何？
• RQ4 选举激励在多大程度上缓解了少数族裔议员在建立跨群体立法联盟时所面临的劣势？
• RQ5 非裔/拉美裔占多数的选区在多大程度上影响了国会议员之间的跨群体支持动态？

主要发现

• 由于基于种族的同群混合，非裔议员在共sponsor方面面临相对劣势：在非裔人口占比低于1.4%的选区，议员共sponsor非裔法案发起人的概率为0.04。
• 在非裔人口占比达32.66%的选区，该概率上升至0.41，表明选举压力效应显著。
• 拉美裔议员也因种族同群效应而处于劣势：在拉美裔人口占比低于1.3%的选区，共sponsor概率为0.04，而在拉美裔人口占比超过34.54%的选区，该概率上升至0.11。
• 女性议员未面临类似劣势；男性议员对共sponsor女性同事的偏好略高于男性同事，表明性别同群效应较弱。
• 选区多样性对共sponsor的影响对非裔和拉美裔议员而言更稳定且更显著，而对女性议员则较弱，表明选举激励对种族/族裔代表制比对性别代表制更具影响力。
• 总体而言，多样化选区中的选举压力显著缓解了少数族裔议员的结构性劣势，尤其体现在非裔和拉美裔议员获得跨群体支持的可能性提升方面。