Matias Iaryczower - Associate Professor of Politics - Princeton University.   

My field of research is Political Economy. I use game theory and empirical methods to study how institutions and strategic considerations shape collective decision-making in courts, legislatures, and elections. 

One of the main lines of my theoretical research is the study of Power and Bargaining in Collective Bodies. I have studied the determinants of the power of leaders in organizations,  the role of intermediaries in legislative bargaining, and whether competition between principals for influence over a group can be detrimental to its members.  I am also interested -- and have written about -- electoral competition and political agency. My empirical work builds on the Structural Estimation approach.  A key theme of my work in this area has been to understand how groups incorporate information about the relative merits of the alternatives under consideration into their decision-making process. My current empirical research focuses on the estimation of dynamic games in Congress and elections.  [CV]. 

Working Papers

Incumbent politicians seeking reelection face an inherently dynamic problem: they observe the  change in their poll standing and incoming contributions, and respond by adjusting their political stances and by spending money in political advertising. In this paper, we formulate a model that captures this problem and estimate the model using data for US senators.  Our empirical strategy allows us to obtain an estimate of senators' policy preferences that discounts pandering.  This approach contrasts with current methods to estimate legislators' ideal points, which assume that all votes are sincere expressions of preference. The difference is consequential: we find that while there are some truly extreme senators, the vast majority is actually relatively moderate, and appear extreme due to electoral pressures. This finding contrasts with the conventional  wisdom on the polarization of elites in american politics.

    We consider a class of dynamic collective action problems in which a principal uses transfers to rally the support of a group of agents, in a context in which agents decisions are sequential and irreversible. We show that whenever the principals'  provide value to the members of the group, introducing competition from a second principal reduces agents' welfare. 

    We estimate a model of voting with incomplete information in which committee members (judges in the US courts of appeals) can communicate before voting. We compare the probability of mistakes with deliberation with a counterfactual of no communication. We find that deliberation can be useful when judges tend to disagree ex ante and their private information is relatively imprecise; otherwise, it tends to reduce the effectiveness of the court.  

    Campaign Contributions have a large effect on the behavior of individual judges -- affecting the probability that they vote to overturn and the probability that they vote incorrectly -- but have a small effect on the decisions and effectiveness of the Court.

    We characterize the optimal contract in a principal-agent relationship when the principal can decide both the direction and implementation scale of a policy. The optimal separating contract is equivalent to delegation "with strings attached": an agent with an upward policy bias can only choose higher policies by reducing the scale of the project. Moreover,  the solution is ex-post inefficient, as the highest policies are too low for both principal and agent and are underfunded relative to the first best.    
    We consider strategic voting in sequential committees in a common value setting with incomplete information. We show that the tally of votes in the  originating committee can aggregate and transmit relevant information for members of the second committee in equilibrium, and provide conditions for the composition and size of committees under which this occurs.

    Selected Publications

    In a model of decentralized bargaining in legislatures, we show that some parties can endogenously emerge as brokers in equilibrium, transferring resources and voting rights between two parties that wouldn't negotiate directly with one another.

    We argue that a model of judicial behavior that accounts for differences in ability and ideology among justices provides a fruitful alternative for the empirical analysis of judicial decision-making around the world, and illustrate this by focusing in the case of the UK. We show that the model explains the decisions of the Lords of Appeal remarkably well, and improves the fit of the ideological model of an ideological model. We use our estimates to tackle previously unaddressed questions about the relative role of ideology and ability in the Appellate Committee

    We estimate an empirical model of voting in Congress that accounts for uncertainty and private information about the quality of the proposal. We show that seniority and uncompetitive elections lead to higher ideological rigidity and curtail the role of information in policy-making.

    We estimate a model of voting in Congress that allows for dispersed information about the quality of proposals in an equilibrium context. The results highlight the effects of bicameralism on policy outcomes. In equilibrium, the Senate imposes an endogenous supermajority rule of about four-fifths on members of the House. 

    Proportional elections have more candidates, competing less aggressively in campaign spending, than those in majoritarian elections. 

    Justices that are shielded from voters' influence on average (i) have better information, (ii) are more likely to change their preconceived opinions about a case, and (iii) make less mistakes than their elected counterparts.  

    We estimate an equilibrium model of decision-making in the Court that takes into account both private information and ideological differences between justices. Our results suggest a sizable value of information in the court: in roughly one out of two cases, justices' initial leanings (given by their prior beliefs and ideological biases) are overpowered by their case-specific information. 

    Spending caps and compulsory voting can be pro-competitive in non-majoritarian electoral systems, leading to a larger number of parties contesting the election.

    Party discipline is endogenously determined by backbenchers' beliefs about the extent of support to the leader within the party. We show that rewards/punishments that can be distributed publicly and on the spot (as opposed to promises of future benefits) are necessary for the leader to be powerful.

    We provide conditions for judicial decisions to be sensitive to legislative lobbying, and find that lobbying falls the more divided the legislature is on the relevant issues. We apply this framework to analyze supreme court labor decisions in Argentina.

    We examine the independence of Argentina's Supreme Court. Our results show an often defiant Court subject to constraints. The probability of voting against the government increases the less aligned a justice is with the President, but falls the stronger the control of the President over the legislature. 

    Work in Progress   

    • "Intertemporal Discrimination in Sequential Contracting", with Santiago Oliveros.
    • "Competing Public Goods", with Nemanja Antic and Santiago Oliveros.
    • "President Blotto", with Gabriel Katz and Gabriel Lopez Moctezuma.
    • "The Causal Effect of Campaign Contributions on Legislators' Voting Behavior", with Gabriel Lopez Moctezuma. 
    • "Choosing Policy-Makers: Learning From Past Decisions in a Changing Environment", with Andrea Mattozzi and Juha Tolvanen. 

    Current Students

    • Gabriel Lopez Moctezuma (main advisor): Political Economy / Quantitative Methods.
    • Svetlana Kosterina (main advisor): Political Economy.
    • Brandon de la Cuesta (com. member): Comparative Politics / Quantitative Methods.
    • Carlos Velazco (com. member): Comparative Politics  / Quantitative Methods.
    • Romain Ferrali (com. member): Comparative Politics.
    • Ted Enamorado (com. member): Quantitative Methods / Comparative Politics.
    • Amanda Kennard (com member): International Relations.


    • Jidong Chen (com. member): Formal Theory / Comparative Politics (Postdoc, Wallis Institute of Political Economy, U. of Rochester).
    • Peter Buisseret (com. member): Formal Theory / Comparative Politics (Asst. Prof., Harris School of Public Policy, U. of Chicago).

    Other Working Papers and Publications (In Spanish)

    • The Institutional Sources of Development in Argentina. Towards an Institutional Agenda. 2000. Editorial Universitaria de Buenos Aires  UNDP-CEDI. Project Directors: Mariano Tommasi and Pablo Spiller.