Natural and agricultural resources for which there is a substantial black market, such as coca, opium, and diamonds, appear especially likely to be exploited by the parties to a civil conflict. On the other hand, these resources may also provide one of the few reliable sources of income in the...

The past half-century has seen economic research become increasingly empirical, while the nature of empirical economic research has also changed. In the 1960s and 1970s, an empirical economist's typical mission was to “explain” economic variables like wages or GDP growth. Applied...

This paper reports updated findings from a randomized evaluation of a generous, privately-funded scholarship program for Nebraska public college students. Scholarship offers boosted college enrollment and persistence. Four years after award receipt, randomly-selected scholarship winners were 13...

Ride-hailing drivers pay a proportion of their fares to the ride-hailing platform operator, a commission-based compensation model used by many internet-mediated service providers. To Uber drivers, this commission is known as the Uber fee. By contrast, traditional taxi drivers in most US cities...

Does academic economic research produce material of scientific value, or are academic economists writing only for clients and peers? Is economics scholarship uniquely insular? We address these questions by quantifying interactions between economics and other disciplines. Changes in the impact of...

Economists have long debated over what labor supply has to do with fluctuations in hours worked. This paper uses a time series of cross-sections from the 1964-88 Current Population Surveys to study whether microeconomic intertemporal substitution models can explain time series fluctuations in...

The relationship between teachers' characteristics and their pupils' achievement has been the subject of many studies. Most of this research focuses on the impact of teacher salaries, experience, and measures of teachers' pre-service training such as educational background. The effect of...

Instrumental Variables (IV) methods identify internally valid causal effects for individuals whose treatment status is manipulable by the instrument at hand. Inference for other populations requires some sort of homogeneity assumption. This paper outlines a theoretical framework that nests all...

Problems of sample selection arise in the analysis of both experimental and non-experimental data. In clinical trials to evaluate the impact of an intervention on health and mortality, treatment assignment is typically nonrandom in a sample of survivors even if the original assignment is random....

Quantile regression(QR) fits a linear model for conditional quantiles, just as ordinary least squares (OLS) fits a linear model for conditional means. An attractive feature of OLS is that it gives the minimum mean square error linear approximation to the conditional expectation function even...