Knowledge that Transforms

We present and calibrate a dynamic model that characterizes the labor market for computer scientists. In our model, firms can recruit computer scientists from recently graduated college students, from STEM workers working in other occupations or from a pool of foreign talent. Counterfactual simulations suggest that wages for computer scientists would have been 2.8-3.8% higher, and the number of Americans employed as computers scientists would have been 7.0-13.6% higher in 2004 if firms could not hire more foreigners than they could in 1994. In contrast, total CS employment would have been 3.8-9.0% lower, and consequently output smaller.

By examining the ethnic identity of authors in over 2.5 million scientific papers written by US-based authors from 1985 to 2008, we find that persons of similar ethnicity coauthor together more frequently than predicted by their proportion among authors. The greater homophily is associated with publication in lower-impact journals and with fewer citations. Meanwhile, papers with authors in more locations and with longer reference lists get published in higher-impact journals and receive more citations. These findings suggest that diversity in inputs by author ethnicity, location, and references leads to greater contributions to science as measured by impact factors and citations.

Paul Samuelson's Foundations of Economic Analysis played a major role in defining how economic theory was undertaken for many years after the Second World War. This paper fills out Samuelson's account of the book's origins and corrects some details, making clear his debt to E. B. Wilson and establishes that turning the thesis into a book was a long process. The contents of the book and its reception are then reviewed.

Important progress has been made in economists' understanding of the Beveridge curve, from its measurement to its expression in canonical labor market models. Yet enduring puzzles remain. Chief among these are the empirical role of vacancies in the recruitment process; the amplitude, comovement, and persistence of cyclical unemployment–vacancy dynamics; and the sources of lateral shifts in the Beveridge curve. The synthesis of these themes identifies several priorities for ongoing research, including the role of entry costs into vacancy creation in shaping Beveridge dynamics; the cyclicality of search intensity, both off and on the job, and its relation to participation and job-to-job transitions; the theory and measurement of mismatch; and the sources of hysteresis in unemployment flows.

I discuss the health transition in the United States, bringing new data to bear on health indicators, and investigating the changing relationship between health, income, and the environment. I argue that scientific advances played an outsize role and that health improvements were largest among the poor. Health improvements were not a precondition for modern economic growth. The gains to health are largest when the economy has moved from "brawn" to "brains" because this is when the wage returns to education are high, leading the healthy to obtain more education. More education may improve use of health knowledge, producing a virtuous cycle.

A growing body of empirical work measuring different types of cultural traits has shown that culture matters for a variety of economic outcomes. This paper focuses on one specific aspect of the relevance of culture: its relationship to institutions. We review work with a theoretical, empirical, and historical bent to assess the presence of a two-way causal effect between culture and institutions.

We propose a novel selectivity correction procedure to deal with survey attrition in treatment effect models, at the crossroads of the Heckit model and the bounding approach of Lee (2009). As a substitute for the instrument needed in sample selectivity correction models, we use information on the number of prior calls made to each individual before obtaining a response to the survey. We obtain sharp bounds to the average treatment effect on the common support of responding individuals. Because the number of prior calls brings information, we can obtain tighter bounds than in other nonparametric methods.

By influencing the size and bargaining power of private insurers, public subsidization of private health insurance may project effects beyond the subsidized population. We test for such spillovers by analyzing how increases in insurer size resulting from the implementation of Medicare Part D affected drug prices negotiated in the non-Medicare commercial market. On average, Part D lowered prices for commercial enrollees by 3.7%. The external commercial market savings amount to $1.5 billion per year, which, if passed to consumers, approximates the internal cost-savings of newly-insured subsidized beneficiaries. If retained by insurers, it corresponds to a 5% average increase in profitability.

This paper shows that poor households’ entitlement to an exogenous, temporary, but guaranteed income stream increases Mexican migration to the United States, although this income is mainly consumed. Some households use the entitlement to this income stream as collateral to finance the migration. The new migrations come from previously constrained individuals and households and worsen migrant skills. In sum, financial constraints to international migration are binding for poor Mexicans, some of whom would like to migrate but cannot afford to. As growth and antipoverty and microfinance programs relax financial constraints for the poor, low-skilled Mexican migration to the United States will likely increase.

This paper proposes a novel matching estimator where neighbors used and weights are endogenously determined by optimizing a covariate balancing criterion. The estimator is based on finding, for each unit that needs to be matched, sets of observations such that a convex combination of them has the same covariate values as the unit needing matching or with minimized distance between them. We implement the proposed estimator with data from the National Supported Work Demonstration, finding outstanding performance in terms of covariate balance. Monte Carlo evidence shows that our estimator performs well in designs previously used in the literature.