We study how best to reward innovators whose work builds on earlier innovations. Incentives to innovate are obtained by offering innovators the opportunity to profit from their innovations. Since innovations compete, awarding rights to one innovator reduces the value of the rights to prior...

We study optimal incentives in a principal-agent problem in which the agent's outside option is determined endogenously in a competitive labor market. In equilibrium, strong performance increases the agent's market value. When this value becomes sufficiently high, the threat of the agent's...

We present an estimated DSGE model of stock market bubbles and business cycles using Bayesian methods. Bubbles emerge through a positive feedback loop mechanism supported by self-fulfilling beliefs. We identify a sentiment shock which drives the movements of bubbles and is transmitted to the...

This paper extends Woodford's (2010) approach to the robustly monetary policy to a general linear quadratic framwork. We provide algorithms to solve for a time-invariant linear robustly optimal policy from a timeless perspective and for a time-invariant linear Markov perfect equilibrium under...

This paper introduces endogenous credit constraints in a search model of unemployment. These constraints generate multiple equilibria supported by self-fulfilling beliefs. A stock market bubble exists through a positive feedback loop mechanism. The collapse of the bubble tightens the credit...

We develop a model of investment with financial constraints and use it to investigate the relation between investment and Tobin's q. A firm is financed partly by insiders, who control its assets, and partly by outside investors. When their wealth is scarce, insiders earn a rate of return higher...

We quantitatively investigate the capacity to collect revenue when the government is constrained to use non-linear (progressive) income taxes. We develop a life-cycle growth model with individual heterogeneity and endogenous labor supply, and explore the degree of tax progressivity that can be...

We present new data documenting medieval Europe's "Commercial Revolution" using information on the establishment of markets in Germany. We use these data to test whether medieval universities played a causal role in expanding economic activity, examining the foundation of Germany's first...

We estimate the full model using Bayesian methods and allow for both determinate and indeterminate equilibria. Our estimates of the resulting equilibria during the Great Inflation of the 1970s reveal that the Fed’s optimal policy response was seen by the private sector as leading to an...

This paper develops a methodology for predicting the impact of trade liberalization on exports by industry (2-digit ISIC) based on the distribution of exports before the reform by product (5-digit SITC). Using the results of Kehoe and Ruhl (2009) that much of the growth in trade after trade...