Content-Based Agendas and Qualified Majorities in Sequential Voting
研究了多个拥有私人信息的投票者在有限选项上具有单峰偏好时的顺序二元投票方案，发现基于内容的议程（从极端到中间）能确保真诚投票构成事后完美均衡，且简单多数下均衡结果总是孔多塞赢家。
We analyze sequential, binary voting schemes in settings where several privately informed agents have single-peaked preferences over a finite set of alternatives, and we focus on robust equilibria that do not depend on assumptions about the players' beliefs about each other. Our main results identify two intuitive conditions on binary voting trees, ensuring that sincere voting at each stage forms an ex post perfect equilibrium. In particular, we uncover a strong rationale for content-based agendas: if the outcome should not be sensitive to beliefs about others, nor to the deployment of strategic skills, the agenda needs to be built “from the extremes to the middle” so that more extreme alternatives are both more difficult to adopt, and are put to vote before other, more moderate options. An important corollary is that, under simple majority, the equilibrium outcome of the incomplete information game is always the Condorcet winner. Finally, we aim to guide the practical design of schemes that are widely used by legislatures and committees and we illustrate our findings with several case studies.