In recent articles, I have argued that integrated assessment models (IAMs) have flaws that make them close to useless as tools for policy analysis. IAM-based analyses of climate policy create a perception of knowledge and precision that is illusory, and can fool policy-makers into thinking that...

We analyze the joint dynamics of religious beliefs, scientific progress and coalitional politics along both religious and economic lines. History offers many examples of the recurring tensions between science and organized religion, but as part of the paper's motivating evidence we also uncover...

Tax-qualified retirement plans seek to promote saving for retirement, yet most employers permit pre- retirement access by letting 401(k) participants borrow plan assets. This paper examines who borrows and why, and who defaults on their loans. Our administrative dataset tracks several hundred...

The largest and most important flow of scientific talent in the world is the migration of international students to the doctoral programs offered by universities in industrialized countries. This paper uses the opening of China in 1978 to estimate the causal effect of this flow on the...

Standard Medicare Part D drug insurance provides limited coverage in a ``donut hole'' region, making the purchase problem dynamic. We develop a discontinuity-based test for myopia using enrollees who arrived near the coverage gap early in the year. We find that there are fewer and cheaper...

We present a model that characterizes the relationship between optimal dynamic cash management and the choice of the means of payment. The novel feature of the model is the sequential nature of the payments choice: in each instant the agent can choose to pay with either cash or credit. This...

We review both the theoretical and empirical literature on entrepreneurship and financial frictions, with an emphasis on the heterogeneous and dynamic micro-level implications of financial frictions for macro development.

In the wake of a severe recession and a sluggish recovery, labor market slack cannot be gauged solely in terms of the conventional measure of the unemployment rate (that is, the number of individuals who are not working at all and actively searching for a job). Rather, assessments of the...

A central prediction of information economics is that market forces can lead businesses to voluntarily provide information about the quality of their products, yet little voluntary disclosure is observed in the field. In this paper, we demonstrate that the inconsistency between theory and...

In the data, wealth is very unequally distributed, even more so than labor earnings and income, and the saving rate of wealthy people is high. Many dynamic models used for quantitative policy evaluation imply that once households get rich, they dissave. As a result, these models generate too...