Several previous studies have relied on religious affiliation and the proximity to Catholic schools as exogenous sources of variation for identifying the effect of Catholic schooling on a wide variety of outcomes. Using three separate approaches, we examine the validity of these instrumental...

We develop estimation methods that use the amount of selection on the observables in a model as a guide to the amount of selection on the unobservables. We show that if the observed variables are a random subset of a large number of factors that influence the endogenous variable and the outcome...

In this paper we develop new estimation methods for identifying causal effects based on the idea that the amount of selection on the observed explanatory variables in a model provides a guide to the amount of selection on the unobservables. Our approach involves the use of factor model as a way...

We develop a framework that may be used to determine the degree to which a school choice program may harm public school stayers by luring the best students to other schools. This framework results in a simple formula showing that the "cream-skimming" effect is increasing in the degree of...

Several previous studies have relied on religious affiliation and the proximity to Catholic schools as exogenous sources of variation for identifying the effect of Catholic schooling on a wide variety of outcomes. Using three separate approaches, we examine the validity of these instrumental...

This article presents a discussion among leading economists on how to do empirical research in economics. The participants discuss their reasons for starting research projects, data base construction, the methods they use, the role of theory, and their views on the main alternative empirical...

This paper considers models for unobservables in duration models. It demonstrates how cross-section and time-series variation in regressors facilitates identification of single-spell, competing risks and multiple spell duration models. We also demonstrate the limited value of traditional...