Knowledge that Transforms

The existence of teacher complementarities across grades can have important implications for the efficient assignment of students to teachers and for the evaluation of teachers using standard value-added models (VAMs). In this paper, I extend the basic VAM to allow for interactive effects between teachers. Using data from North Carolina’s primary schools, I find that teacher complementarities within schools are extremely small. This finding suggests that there is little to gain by assigning students to particular teacher sequences. Moreover, measures of teacher effectiveness generated from a typical VAM are not likely to be biased by interactions with past teacher inputs.

We analyze commitment to employment in an environment in which an infinitely lived firm faces a sequence of finitely lived workers who differ in their ability. A worker’s ability is initially unknown, and a worker’s effort affects how informative about ability the worker’s performance is. We show that equilibria display commitment to employment only when effort has a delayed impact on output. In this case, insurance against early termination encourages workers to exert effort, thus allowing the firm to better identify workers’ ability. Our results help explain the use of probationary appointments in environments in which workers’ ability is uncertain.

Understanding the employment dynamics of disadvantaged families is increasingly important. We estimate duration models describing these dynamics for disadvantaged single mothers and use them to conduct a rich set of counterfactual analyses. We use a misreporting model to correct for “seam bias,” the problem that too many transitions are reported between reference periods in panel data. We find effects of demographics, minimum wages, unemployment rates, and maximum welfare benefits, but not policy changes introduced through state welfare waivers, on employment dynamics. We find that two commonly used ad hoc methods of addressing seam bias perform substantially worse than our approach.

In the past 30 years, wage inequality has increased steeply while real minimum wages have fallen. This paper demonstrates that a general equilibrium model with endogenous skill choice is required to correctly evaluate the implications of minimum wage changes. The minimum wage not only truncates the wage distribution but also affects skill prices and therefore changes the incentives that people face when making educational decisions. The calibrated model suggests—in line with recent empirical literature—that even though minimum wages affect the bottom end of the wage distribution more, their impact on the top end is significant as well.

We empirically investigate the effect of uncertainty on corporate hiring. Using novel data from the labor market for MBA graduates, we show that uncertainty regarding how well job candidates fit with a firm’s industry hinders hiring and that firms value probationary work arrangements that provide the option to learn more about potential full-time employees. The detrimental effect of uncertainty on hiring is more pronounced when firms face greater firing and replacement costs and when they face less direct competition from other similar firms. These results suggest that firms faced with uncertainty use similar considerations when making hiring decisions as when making decisions regarding investment in physical capital.

A substantial empirical literature documents the rise in wage inequality in the American economy. It is silent on whether the increase in inequality is due to components of earnings that are predictable by agents or whether it is due to greater uncertainty facing them. These two sources of variability have different consequences for both aggregate and individual welfare. Using data on two cohorts of American males we find that a large component of the rise in inequality for less skilled workers is due to uncertainty. For skilled workers, the rise is less pronounced.

This paper provides the first evidence that value-added education accountability schemes induce dynamic distortions. Extending earlier dynamic moral hazard models, I propose a new test for ratchet effects, showing that classroom inputs are distorted less when schools face a shorter horizon over which they can influence student performance. I then exploit grade span variation using rich educational data to credibly identify the extent of dynamic gaming and find compelling evidence of ratchet effects based on a triple-differences approach. Further analysis indicates that these effects are driven primarily by effort distortions, with teacher reallocations playing a secondary role.

We document the growth in higher education costs and tuition over the past 50 years. To explain these trends, we develop a general equilibrium model with skill- and sector-biased technical change. Finding the model’s parameters through a combination of estimation and calibration, we show that it can explain the rise in college costs between 1961 and 2009, along with the increase in college attainment and the change in the relative earnings of college graduates. The model predicts that if college costs had ceased to grow after 1961, enrollment in 2010 would have been 3%–6% higher.

Much attention has been given to the large increases in safety net spending during the Great Recession. We examine the relationship between poverty, the safety net, and business cycles historically and test whether there has been a significant change in this relationship. We find that post–welfare reform, Temporary Assistance for Needy Families did not respond during the Great Recession and extreme poverty is more cyclical than in prior recessions. Food Stamps and Unemployment Insurance are providing more protection—or no less protection—in the Great Recession, and there is some evidence of less cyclicality for 100% poverty.