Papers not intended for publication

January 2012
We construct a simple dynamic model of promotion and spinoff formation that sheds some light on why the empirical relationships between spinoff formation, tenure and performance vary so widely across different settings. A supervisor must learn over time about the employee’s aptitude for work at a more senior level and decide whether to promote him. The employee balances the benefits of waiting for promotion against immediate departure to form a spinoff. By means of a number of approximations to the pair of interrelated optimal stopping problems that our model gives rise to, we are able to characterize the effects of parameter changes on the likelihood and timing of promotion and spinoff formation.
April 2011
We construct a simple model of occupational choice among agents with differing abilities. The fraction of agents creating new businesses who are low ability rises during recessions. Thus, cohorts born during recessions are on average lower quality: their businesses yield lower initial earnings, grow more slowly, and are more likely to fail. We show that, because of their effects on the ability distribution of business founders, short-lived recessions can have long-term consequences for the quality of a cohort of firms.
May 2008
This paper presents an explicit model of the entrepreneur’s role in organizing the work undertaken by employees. The model assumes that agents vary in their ability to carry out this task, and so in one sense the model is a special case of Lucas’ [Bell Journal of Economics, 9, pp. 508-523, (1978)] span of control framework. However, the model also relates ability to risk. As in Kihlstrom and Laffont [Journal of Political Economy, 87, pp. 719-748 (1979)], the entrepreneur bears all risk. But while Kihlstrom and Laffont assume the entrepreneur bears all risk and show that as a consequence the least risk averse become entrepreneurs, in the present model all agents are risk neutral but entrepreneurs bear all risk as an equilibrium outcome. The model is used to study the consequences of firm growth driven by entrepreneurial learning or by rising demand. 
September 2010
Contributing Paper for chapter 5 of the 2011 ISDR Global Assessment Report on Disaster Risk Re​duction, United Nations International Strategy for Disaster Reduction Secretariat, Geneva.
August 2008
This article is a supporting document to the paper "Selection and Firm Survival. Evidence from the Shipb​uilding Industry, 1825-1914" [Review of Economics and Statistics, 87(1):26-36, February 2005], and is not intended for publication. The article provides a basic description of data sources, coverage and limitations, along with coding decisions made for the purposes of statistical analysis. ​