SIPA at Columbia
Thomas Groll

home Academic Interests

My main academic interests relate to topics in public economics, industrial organization, political economics, and applied microeconomics. Current research projects focus on commercial lobbying activities, the development of political institutions, and political competition.


"The Economics of Commercial Lobbying"
Dissertation Committee Members: Christopher J. Ellis (Chair), Shankha Chakraborty, Nicholas Sly, Daniel Tichenor (Political Science).

Working Papers
Abstract This study explains why the preponderance of lobbying occurs between policymakers and commercial lobbyists who act as intermediaries for special interests, rather than directly between policymakers and the special interest groups themselves. Commercial lobbyists are for-profit organizations that have no inherent policy bias and interact repeatedly with policymakers; we argue that these characteristics allow them to be incented by policymakers via repeated agency contracts. Using a dynamic model of commercial lobbying, we show that policymakers select a point on the lobbyist's incentive compatibility constraint which represents a contract involving a mix of financial contributions and information on policy proposals. This contract is shown to solve both an information problem in the presence of unverifiable policy information, and a contracting problem in the absence of legally binding contracts. Both the distribution of the benefits and welfare implications arising from the introduction of repeated agency depend upon the relative weights placed by the policymaker on solving the information and contracting problems. Relative to the full information social welfare optimum the policymaker may place too much or too little weight on socially beneficial policy information relative to privately beneficial financial contributions.

Current Version: November 2014.
Supplemental Appendix
Previous working paper: CESifo WP 4114.

Abstract We develop a model of informational lobbying that combines costly persuasion with legislative subsidies. In contrast to other models of informational lobbying we focus on the implications of a policymaker's and a lobby's resource constraints for lobbying activities and the political process. Both a policymaker and a lobby can gather information, and each can either fund or subsidize a policy reform. We show that a lobby is more likely to persuade a policymaker to change her anticipated behavior of gathering information or choosing a policy, if the precision of the information signals received by the lobby is more asymmetric rather than better or if information costs are lower. We also show that a lobby is more likely to persuade critical to optimistic policymakers and more likely to support those financially. By varying resource endowments, we address whether costly persuasion and financial contributions as legislative subsidies are substitutes or complements in the lobbying process and derive the conditions for each. Additionally, we discuss the relationship between costly persuasion and financial information subsidies in the case of an entirely resource constrained policymaker. Our results point out additional difficulties to identify empirically the role of contributions as legislative subsidies which may appear as bribery and the shadow lobbying of interest groups.   

Current version: December 2014.
Supplemental .nb file: upon request.

Abstract This paper analyzes the effective regulation of commercial lobbying activities and focuses on the endogenous choice of regulatory institutions. The analysis uses a model of commercial lobbying in which citizens hire lobbyists to present policy matters on their behalf, and policymakers announce political access rules to induce citizens and lobbyists to engage in information acquisition and make financial contributions. The distribution of private costs and public informational benefits from commercial lobbying can explain why commercial lobbying is widely employed, but may not be socially efficient, and may lack public support. I derive the institutional conditions under which a market outcome can be first-best as well as the conditions under which a first-best institution will or will not be self-stable. One result is that current lobbying regulation may fail to be effective: unable to limit lobbyists' and policymakers' incentives to substitute financial contributions for socially beneficial information acquisition. The analysis highlights the necessity to monitor information transfers as well as financial transfers to construct effective regulatory instruments. Additional results explain why endogenous reforms that regulate lobbying activities may or may not occur.

Current version: March 2013.


Abstract In this paper we present a model of the behavior of commercial lobbying firms (such as the so-called K-Street lobbyists of Washington, D.C.). In contrast to classical special interest groups, commercial lobbying firms represent a variety of clients and are not directly affected by policy outcomes. They are hired by citizens, or groups of citizens, to act as intermediaries on their behalf with policymakers. In our analysis we address two basic questions; what tasks are commercial lobbying firms performing, and what are the implications of their existence for social welfare? We answer the first part of this question by proposing that commercial lobbying firms possess a verification technology that allows them to improve the quality of information concerning the social desirability of policy proposals. This gives policymakers the incentive to allocate their scarce time to commercial lobbying firms. Essentially, it is this access to policymakers that commercial lobbying firms sell to their clients. To address the question of social welfare we construct a simple general equilibrium model that includes commercial lobbying firms, and compare the equilibrium obtained under market provision of lobbying services to the first-best optimum. We find that the market level of lobbying services can be socially either too large or too small, and characterize when each will be the case.

Supplemental Appendix
Previous (longer) working paper: CESifo WP 4110.
Abstract An income growth pattern is pro-poor if it reduces a (chosen) measure of poverty by more than if all incomes were growing equiproportionately. Inequality reduction is not sufficient for pro-poorness. In this paper, we explore the nexus between pro-poorness, growth and inequality in some detail using simulations involving the displaced lognormal, Singh-Maddala and Dagum distributions. For empirically relevant parameter estimates, distributional change preserving the functional form of each of these 3-parameter distributions is often either pro-poor and inequality reducing, or pro-rich and inequality exacerbating, but it is also possible for pro-rich growth to be inequality reducing. There is some capacity for each of these distributions to show trickle effects (weak pro-richness) along with inequality-reducing growth, but virtually no possibility of pro-poorness for growth which increases overall inequality. Implications are considered.
Previous (longer) working paper: ECINEQ Working Paper No. 2011-214.
Works in Progress

  • Whom to Lobby? with Anja Prummer. [draft coming soon]
  • Costly Persuasion and Resource Constraints with Competitive Lobbies with Christopher J. Ellis.
  • Commercial Lobbying and Political Competition with Christopher J. Ellis.
  • Lobbying with Motivated Agents with Christopher J. Ellis.