Carlos R. Lever
Job Market Candidate

Stanford University
Department of Economics
579 Serra Mall
Stanford, CA 94305
650-644-9052
carloslever@stanford.edu

Research

“A model of political campaigns, marketing and lobbying over social networks: whom to target?”
(Job Market Paper.)

I study situations where two groups (political parties, lobbies or firms) compete by spending resources on individuals to convince them to choose them. The individuals are also influenced by the opinion of their neighbors on a social network. Groups must decide whom to target to maximize the impact of their resources. I find that equilibrium spending targets resources toward individuals with higher network influence while adjusting to spend less on individuals who are harder to persuade. This contrasts with models on strategic spending without network influence, which had found that parties (or lobbies) would spend more on individuals who have a higher probability of being pivotal voters. To test my model I matched data on cosponsorship networks in Congress with data on campaign contributions by lobbies. Both network influence and pivot probabilities are statistically significant predictors of lobby spending, but the estimate of network influence is larger.

“Price competition on a buyer-seller network.” (Working paper. Revised February 2009)

In infrastructure networks, not all firms can sell to all consumers. Different network configurations can have complicated effects on pricing and welfare. We extend the two firm Bertrand competition model to study these situations. For each network I solve for the a unique equilibrium in pricing strategies. Except for degenerate networks, the equilibrium involves mixing over a continuous interval. In equilibrium, aggregate surplus increases monotonically as the network becomes more connected. When firms decide how to build infrastructure, stable networks emerge that are midway between the network with perfect competition (maximum efficiency) and networks with local monopolists (maximum inefficiency). The results extend for more than two firms under certain network structures.

“The leverage of weak ties: how connecting social groups changes investment decisions.” Joint work with Ben Golub. (Work in progress. Revised October 2009)

We study an investment game where individuals make an investment decision with positive spillovers from their neighbors on a social network. In equilibrium, when social effects are strong, equilibrium investment choices are well-approximated by eigenvector centrality. We then analyze the effect of connecting separate social groups. We find that if an influential member of group A is linked to an uninfluential member of group B, then group B will have a disproportionate influence in the equilibrium investment after the groups are connected. Even though the relative influence across groups can change dramatically as a result of arbitrarily weak intergroup ties, the  relative influence within each group remains essentially the same.

“Lorenz undominated points in a facility-location problem.” (Working paper. Revised March 2009)

An important dilemma in welfare economics is the trade-off between equality and surplus maximization, but this trade-off is not always present. Lorenz undominated points identify policies were there is no trade-off: either it’s no longer possible to improve aggregate surplus without increasing inequality, or to decrease inequality without decreasing aggregate total surplus. Unfortunately, these are hard to compute. We present an algorithm for finding Lorenz undominated points in an interesting social choice problem: where to place a desirable facility on an interval. In developing the algorithm we are able to highlight some interesting properties of Lorenz undominated points: they come from take averages from the worst-off individuals in society, they shrink under concave transformations and they form a convex set.

Teaching

Courses I’ve taught:

1. - Contract and Auction Theory for Undergraduates. Summer 2005 at the Instituto Tecnológico Autónomo de México. (ITAM)
   
   

2. - Globalization and New World Order. Stanford’s Extension Program for the Gifted Young (EPGY), Singapore 2008. Three-week course on basic microeconomic theory, growth theory and welfare economics.
   
   

3. - International Business. EPGY, London 2009. Three-week course on basic microeconomic theory, organization theory and financial markets.
   

Courses I’ve TA-ed:

1. - Graduate Microeconomics. Consumer and producer theory, general equilibrium, choice under uncertainty. Profs. Luigi Pistaferri and Ilya Segal. Fall 2008.
   
   

2. - Graduate Microeconomics. Information economics, cooperative game theory, general equilibrium with uncertainty. Prof. Matt Jackson. Spring 2008.
   
   

3. - Intermediate Microeconomics. Outstanding teaching award, Fall 2007.
   
   

4. - Intermediate Macroeconomics. Outstanding teaching award, Spring 2009.
   
   

5. - Graduate Game Theory. ITAM Spring 2005. 
   

Student evaluations:

    Graduate micro.pdf

    Intermediate micro.pdf

    Intermediate macro.pdf