Matias Iaryczower - Associate Professor of Politics - Princeton University  My fields of research are Political Economy and Positive Political Theory. I study how institutions and strategic interactions shape collective decision-making in legislatures, courts and electorates. I approach these issues from both a theoretical and an empirical perspective, developing  applications of Game Theory and Structural Estimation in Economics and Political Science. I teach Game Theory and its applications to Politics to graduate and undergraduate students.  [CV


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 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 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.  

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

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 they have a small effect on the decisions and effectiveness of the Court.

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. 

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

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

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. 

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.

Changes in the cost of running for office or shifts in the cost of increasing the perception of quality induce a positive correlation between the equilibrium number of candidates running for office and their campaign spending. 

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.

  • "The Supreme Court," with Pablo T. Spiller and Mariano Tommasi, in Pablo Spiller and Mariano Tommasi (eds.), The Institutional Foundations of Public Policy in Argentina: A Transaction Cost Approach, 2007, Cambridge University Press.

Argentina's Supreme Court in the broader political context. 

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   

  • "Senate Dynamics in the Shadow of Money", with Gabriel Lopez Moctezuma and Adam Meirowitz. 
  • "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.
  • "Strategic Political Marketing", with Jidong Chen.
  • "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. 


Students (in Committee)

  • Gabriel Lopez Moctezuma (main advisor): Comparative Politics / Quantitative Methods / Formal Theory (at Princeton)
  • Brandon de la Cuesta: Comparative Politics / Quantitative Methods (at Princeton)
  • Carlos Velazco: Comparative Politics / Quantitative Methods (at Princeton)
  • Jidong Chen: Formal Theory / Comparative Politics (Postdoc, Wallis Institute of Political Economy, U. of Rochester)
  • Peter Buisseret: Formal Theory / Comparative Politics (Asst. Prof, Dept. of Economics; Warwick U.)

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.