Knowledge that Transforms

Systemic risk must include the housing market, though economists have not generally focused on it. We begin construction of an agent-based model of the housing market with individual data from Washington, DC. Twenty years of success with agent-based models of mortgage prepayments give us hope that such a model could be useful. Preliminary analysis suggests that the housing boom and bust of 1997-2007 was due in large part to changes in leverage rather than interest rates.

When a city experiences a decline in income or population, do all neighborhoods within the city decline equally? Or, do some neighborhoods decline more than others? What are the characteristics of the neighborhoods that decline the most? We answer these questions by looking at what happened to neighborhoods within Detroit as Detroit experienced a sharp decline in income and population from the 1980s to the late 2000s. We find patterns of changes in income and population that are consistent with the model and empirical patterns of gentrification presented in Guerrieri, Hartley, and Hurst (2011), only playing out in reverse.

We propose an incentive scheme for educators that links compensation to the ranks of their students within comparison sets. Under certain conditions, this scheme induces teachers to allocate socially optimal levels of effort. Moreover, because this scheme employs only ordinal information, it allows education authorities to employ completely new assessments at each testing date without ever having to equate various assessments. This removes incentives for teachers to teach to a particular assessment form and eliminates opportunities to influence reward pay by corrupting assessment scales. Education authorities can employ separate no-stakes assessment systems to track trends in scaled measures of student achievement. (JEL I21, I28, J33, J45)

This study explores the determinants of ethnolinguistic diversity within as well as across countries shedding light on its geographic origins. The empirical analysis conducted across countries, virtual countries and pairs of contiguous regions establishes that geographic variability, captured by variation in regional land quality and elevation, is a fundamental determinant of contemporary linguistic diversity. The findings are consistent with the proposed hypothesis that differences in land endowments gave rise to location-specific human capital, leading to the formation of localized ethnicities.

Examination of detailed geographical information on U.S. housing transactions from 1993 to 2009 find much heterogeneity at the neighborhood level in when the recent boom began, how big the initial jumps in price growth were, how long the booms lasted, and what types of neighborhoods boomed first. There is less neighborhood-level heterogeneity in when the bust began and in aggregate price appreciation during the boom. This heterogeneity suggests that there was no one dominant cause of the boom. We also comment on how very local data may help understand the role of contagion, among other housing market phenomena.

We use a model of human capital investment and activity choice to explain facts describing gender differentials in the levels and returns to human capital investments. These include the higher return to and level of schooling, the small effect of healthiness on wages, and the large effect of healthiness on schooling for females relative to males. The model incorporates gender differences in the level and responsiveness of brawn to nutrition in a Roy-economy setting in which activities reward skill and brawn differentially. Empirical evidence from rural Bangladesh provides support for the model and the importance of the distribution of brawn.

We combine matched Danish worker-firm-trade data with detailed individual-worker training data. We find: 1) workers displaced from offshoring firms take up more vocational-training and have a harder time getting re-attached to the labor-force than other displaced workers, and they also exhibit higher vocational-training take-up rates 2 years before layoffs; 2) the staying workers with offshoring firms take up more vocational-training than those with non-offshoring firms; and 3) the post-secondary-training take-up rates for displaced workers are no different than for the general population.

The labor market in the Great Recession and its aftermath is characterized by great difficulty in escaping unemployment. I present two empirical analyses of a particular explanation for that difficulty, that the housing market crisis has prevented the unemployed from selling their homes and moving to take new jobs. First, I examine post-job-loss mobility rates by home ownership status using data from the Displaced Workers Survey. Second, I examine mobility rates for unemployed homeowners and renters from the month-to-month CPS match. Neither analysis provides any support for the idea that the housing market crisis has reduced mobility of the unemployed.

GDP growth is often measured poorly for countries and rarely measured at all for cities or subnational regions. We propose a readily available proxy: satellite data on lights at night. We develop a statistical framework that uses lights growth to augment existing income growth measures, under the assumption that measurement error in using observed light as an indicator of income is uncorrelated with measurement error in national income accounts. For countries with good national income accounts data, information on growth of lights is of marginal value in estimating the true growth rate of income, while for countries with the worst national income accounts, the optimal estimate of true income growth is a composite with roughly equal weights. Among poor-data countries, our new estimate of average annual growth differs by as much as 3 percentage points from official data. Lights data also allow for measurement of income growth in sub- and supranational regions. As an application, we examine growth in Sub Saharan African regions over the last 17 years. We find that real incomes in non-coastal areas have grown faster by 1/3 of an annual percentage point than coastal areas; non-malarial areas have grown faster than malarial ones by 1/3 to 2/3 annual percent points; and primate city regions have grown no faster than hinterland areas. Such applications point toward a research program in which "empirical growth" need no longer be synonymous with "national income accounts."

This paper analyzes the effect on performance and earnings of delegating the wage choice to employees. Our results show that such delegation significantly increases effort levels. Moreover, we observe a Pareto improvement, as the earnings of both employers and employees increase when employers delegate than when they do not. Interestingly, we also find that the employees' performance under delegation is higher than under nondelegation, even for similar wages. While there is strong evidence that behavior reflects strategic considerations, this result also holds for one-shot interactions. A possible nonstrategic motivation explaining the positive reaction to delegation is a sense of enhanced responsibility. (JEL J31, J33, J41)