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This dissertation applies tools developed in labor economics to empirically study questions in labor, development, and urban economics. Each chapter attempts to decompose a problem into competing explanations. The first decomposes racial segregation in US cities. The second decomposes differences in wages between agricultural workers and and non-agricultural workers. And finally, the last decomposes the heterogeneous responses of workers to a new monitoring technology.In the first chapter, I revisit the question of whether residential segregationin US cities emerged in the mid-twentieth century as a consequence of decentralized location choices in combination with white antipathy toward black residents or whether it reflected institutionalized constraints on the availability of neighborhoods that black families could access. The chapter analyzes rich population data from the 1930 and 1940 censuses to disentangle these channels. I first lay out a simple discrete choice model of residential choices by white and black families that depends on the local price of housing and on the fraction of black residents in each neighborhood. I show how the preferences of both race groups can be identified using information on the impacts of exogenous inflows of white and black residents to different neighborhoods. White and black rural inflows constituted a major source of inmigration to major cities during this time period; I construct a pair of novel instrumental variables for these inflows by connecting the distributions of white and black surnames in rural areas to earlier migrants living in different census tracts in 1930. The resulting structural estimates confirm that white families had a relatively high willingness to pay to avoid black neighbors, consistent with an important role for preferences in the evolution of neighborhood segregation. Combining white and black preferences, however, I also find strong evidence that black residents faced supply side constraints on their neighborhood choices. I conclude that about one half of the overall degree of neighborhood segregation observed in 1940 was due to the different preferences of white and black families, while a comparable share was due to implicit or explicit constraints on which neighborhoods black families could move into.While the first chapter interpreted incumbent residents' responses to migrants as reflective of their racial preferences, the second chapter, based on joint work with Marieke Kleemans, Joan Hamory Hicks, and Ted Miguel, directly studies the migrant experience itself. Recent research has pointed to large gaps in labor productivity between the agricultural and non-agricultural sectors in low-income countries, as well as between workers in rural and urban areas. Most estimates are based on national accounts or repeated cross-sections of micro-survey data, and as a result typically struggle to account for individual selection between sectors. We use long-run individual-level panel data from two low-income countries (Indonesia and Kenya). Accounting for individual fixed effects leads to much smaller estimated productivity gains from moving into the non-agricultural sector (or urban areas), reducing estimated gaps by over 80%. Estimated productivity gaps do not emerge up to five years after a move between sectors. We evaluate whether these findings imply a re-assessment of the conventional wisdom regarding sectoral gaps, discuss how to reconcile them with existing cross-sectional estimates, and consider implications for the desirability of sectoral reallocation of labor.Finally, the third chapter is based on joint work with Ernesto Dal Bó, Frederico Finan, and Laura Schechter and empirically studies models of task assignment within organizations in a developing country context. Standard models of hierarchy assume that agents and middle managers are better informed than principals about how to implement a particular task. We estimate the value of the informational advantage held by supervisors (middle managers) when ministerial leadership (the principal) introduced a new monitoring technology aimed at improving the performance of agricultural extension agents (AEAs) in rural Paraguay. Our approach employs a novel experimental design that, before randomization of treatment, elicited from supervisors which AEAs they believed should be prioritized for treatment. We find that supervisors did have valuable information---they prioritized AEAs who would be more responsive to the monitoring treatment. We develop a model of monitoring under different allocation rules and roll-out scales (i.e., the share of AEAs to receive treatment). We semi-parametrically estimate marginal treatment effects (MTEs) to demonstrate that the value of information and the benefits to decentralizing treatment decisions depend crucially on the sophistication of the principal and on the scale of roll-out.

With advancements in sequencing technology there has been an unprecedented rise in human single nucleotide variant data in recent years. One of the key challenges within clinical genetics is distinguishing truly pathogenic from rare but benign variants. Many in silico tools have been developed with this aim but they often over predict pathogenicity particularly on novel variants. Here, I demonstrate how a framework designed to identify variants with functional equivalence by using information from variants in known related genes can help pathogenic variant interpretation. Using sequence alignments of human paralogues, known pathogenic variants within aligned positions can be used to transfer their annotations across to aligned variants. This Paralogue Annotation method is shown to be widely applicable exome-wide, with 71% of disease genes having at least one paralogue. As a classifier it performs more precisely than other contemporary variant predictors, having a precision of 94% or higher depending on the data. This however comes at the cost of limited sensitivity (17% and lower). But this is rescued when the framework was improved by altering the alignments to protein domains instead of whole gene sequences. The sensitivity was increased by 74% with a marginal 6% precision decrease. By expanding the framework to explore the usage of structural protein alignments instead of sequence alignments there is potential to further improve sensitivity, but current limited structural data means that predicted protein models must be relied on leading to further assumptions to be taken. In structural space, pathogenic variants across aligned models are statistically more likely to be closer together than benign and pathogenic variants. This framework can be used as a precise pathogenic variant classifier in sequence space, but overall, it can be used to search for functionally equivalent variants to variants of interest, which is a line of information not used by many. Open Access

Acetaminophen overdose is one of the most common causes of acute hepatic failure in the developed world. There is strong evidence for N-acetylcysteine (NAC) as a safe and effective antidote for acetaminophen toxicity. However, there is less clarity in the management of massive overdoses (acute, single ingestions>500 mg/kg with 4-hour equivalent concentrations ~6000 μmol/L) which are often associated with metabolic acidosis and multiorgan dysfunction. In such ingestions, the role of adjuvant treatments such as fomepizole and extracorporeal removal is unclear. We present a case of a 20-year-old female presenting with an acute ingestion of over 120 grams (1764.7 mg/kg) and an acetaminophen concentration of 5880 μmol/L who developed refractory shock, decreased level of consciousness, and metabolic acidosis requiring mechanical ventilation and vasopressor support. She was treated with gastric decontamination with activated charcoal, IV NAC, fomepizole, and hemodialysis. The patient had complete clearance of acetaminophen by 32 hours after presentation and normalization of her acid base and hemodynamic status without any organ failure. This case highlights the potential benefit of a triple strategy of NAC, fomepizole, and early hemodialysis in massive acetaminophen overdose, potentially sparing complications of prolonged intubation and ICU hospitalization.

Total energy expenditures for the Indian population between 1983 and 2012 are estimated to shed light on the debate concerning falling measured caloric intake during the period (Deaton and Dre ze 2009). Anthropometric, time-use, and detailed employment surveys are used to estimate the separate components of total energy expenditure related to metabolism and physical activity levels. Despite a significant drop in adult physical activity levels, total energy expenditures are flat overall between 1983 and 2012. Rising metabolic requirements due to increases in weight dampened the effect of falling activity levels on total energy expenditure. In addition, the 10 percent decline in the population share of children in the period raised average total energy expenditures considerably as children have much lower metabolic requirements and activity levels than adults.

Standard analysis of consumer behavior uses theory and evidence on quantities and prices to measure consumer welfare, particularly through the use of price indexes that capture the cost-of-living. In three essays I go beyond this standard analysis to analyze the impact of household variety, store variety, and energy requirements on food demand, consumption patterns and consumer welfare, with implications for several important topics in development and international economics. In the first essay I develop theoretical and empirical tools for analyzing variety-seeking behavior by households in a non-homothetic setting, showing how changes in the slope and intercept of ``variety Engel curves'' map into the level and distribution of consumer welfare in a way that is not captured by standard analysis. The ``cost'' of variety is introduced as an important concept for analysis that is distinct from price, e.g. the ``cost'' of quantity. The application to Indian food consumption indicates that increases in food variety over time and greater urban food variety are not attributable solely to income growth, with significant implications for both the size and distribution of welfare gains from variety. In the second essay, co-authored with Shari Eli, we continue to explore empirical patterns in Indian food consumption and draw attention to the decline in calorie intake at all expenditure levels. Once again the Engel curve is used as a guiding framework for the empirical analysis and once again there are changes in consumption patterns that are not explained by movements in prices and income alone. In this case the ``cost'' of calories is represented by the role of calories (as opposed to other food attributes) in satisfying household caloric requirements. Using data on time-use to impute caloric requirements and combining this with data on ownership of labor-saving durables, we find support for the hypothesis that a decline in energy requirements has had an important impact on variation in calorie intake over time and space, explaining most of the rural-urban discrepancy in calorie intake but only a modest share of the decline in calorie intake over time. In the third essay I examine product variety from the point of view of retailers rather than consumers, showing that differences in variety across different stores of a North American grocery retailer have large impacts on consumer welfare. I argue that these differences in variety can be largely attributed to differences in store size and international borders, and provide a stylized partial equilibrium model to analyze what factors influence the retailer's choice of store size in different locations. I find empirical support for the predictions of the model, with larger markets (higher income per capita, higher population density) leading to larger store size and variety while greater competition reduces store size and variety, with significant impacts on consumer welfare across different geographic areas.

Supplementary figures S1 and S2. (DOCX 742 kb)

While bans against child labor are a ubiquitous policy tool, there is very little empirical evidence on their effectiveness. In this paper, we examine the consequences of India's landmark legislation against child labor, the Child Labor (Prohibition and Regulation) Act of 1986. Using data from employment surveys conducted before and after the ban, and using age restrictions that determined whom the ban applied to, we show that the relative probability of child employment increases and child wages (relative to adult wages) decrease after the ban. Our main specification relies on comparing changes in work probabilities over time for children of the same age but with siblings who are rendered either eligible or ineligible for legal work when the ban is implemented. The increases in the probability of economic activity are largest for children in areas where (i) the industries targeted by the ban play a larger role in local labor markets and (ii) the probability of employer inspections are higher. These results are consistent with a theoretical model building on the seminal work of Basu and Van (1998) and Basu (2005), where families use child labor to reach subsistence constraints and where child wages decrease in response to bans, leading poor families to utilize more child labor. We also examine the effects of the ban at the household level. Using linked consumption and expenditure data, we find that along the margins of assets and share of staple goods in calorie consumption, households are worse off after the ban.

We examine the extent to which vertical and horizontal market structure can together explain incomplete retail pass-through. To answer this question, we use scanner data from a large U.S. retailer to estimate product level pass-through for three different vertical structures: national brands, private label goods not manufactured by the retailer and private label goods manufactured by the retailer. Our findings emphasize that accounting for the interaction of vertical and horizontal structure is important in understanding how market structure affects pass-through, as a reduction in double-marginalization can raise pass-through directly but can also reduce it indirectly by increasing market share., Les auteurs s’interrogent sur la mesure dans laquelle la structure verticale d’un marché et sa structure horizontale peuvent ensemble expliquer la transmission incomplète des coûts aux prix de détail. Pour répondre à cette question, ils estiment, à l’aide de données provenant d’un important détaillant américain recueillies par balayage optique, le degré de transmission des coûts selon les produits, pour trois structures verticales différentes : marques nationales, marques de distributeur non fabriquées par le détaillant et marques de distributeur fabriquées par lui. D’après les résultats de l’étude, il faut tenir compte de l’interaction des structures verticale et horizontale si l’on veut comprendre comment la structure d’un marché influe sur le degré de répercussion des coûts, du fait que la réduction de la double marginalisation peut aussi bien faire augmenter directement ce degré que le faire diminuer indirectement par l’élargissement des parts de marché.

To what extent do national borders and national currencies impose costs that segment markets across countries? To answer this question the authors use a dataset with product-level retail prices and wholesale costs for a large grocery chain with stores in the United States and Canada. They develop a model of pricing by location and employ a regression discontinuity approach to estimate and interpret the border effect. They report three main facts: One, the median absolute retail price and wholesale cost discontinuities between adjacent stores on either side of the U.S.-Canadian border are as high as 21 percent. In contrast, within-country border discontinuity is close to 0 percent. Two, the variation in the retail price gap at the border is almost entirely driven by variation in wholesale costs, not by variation in markups. Three, the border gaps in prices and costs co-move almost one-to-one with changes in the U.S.-Canadian nominal exchange rate. They show these facts suggest that the price gaps they estimate provide only a lower bound on border costs.

Coal contains a large number of fractures, whose characteristics are difficult to describe in detail, while their spatial distribution patterns may follow some macroscopic statistical laws. In this paper, several fracture geometric parameters (FGPs) were used to describe a fracture, and the coal seam was represented by a two-dimensional stochastic fracture network (SFN) which was generated and processed through a series of methods in MATLAB. Then, the processed SFN image was able to be imported into COMSOL Multiphysics and converted to a computational domain through the image function. In this way, the influences of different FGPs and their distribution patterns on the permeability of the coal seam were studied, and a finite element model to investigate gas flow properties in the coal seam was carried out. The results show that the permeability of the coal seam increased with the rising of fracture density, length, aperture, and with the decrease of the angle between the fracture orientation and the gas pressure gradient. It has also been found that large-sized fractures have a more significant contribution to coal reservoir permeability. Additionally, a numerical simulation of CBM extraction was carried out to show the potential of the proposed approach in the application of tackling practical engineering problems. According to the results, not only the connectivity of fractures but also variations of gas pressure and velocity can be displayed explicitly, which is consistent well with the actual situation.