Although both economists and psychometricians typically treat them as interval scales, test scores are reported using ordinal scales. Using the Early Childhood Longitudinal Study (ECLS-K) and the Children of the National Longitudinal Survey of Youth (CNLSY), we examine how order-preserving scale...

We examine inference in panel data when the number of groups is small, as is typically the case for difference-in-differences estimation and when some variables are fixed within groups. In this case, standard asymptotics based on the number of groups going to infinity provide a poor...

Almost all labor-supply models are estimated under the assumption that workers are free to choose their hours. However, theory, casual empiricism, and survey data suggest that many workers are not free to vary the hours within a job. Consequently, labor-supply estimates based on actual hours of...

We study the consequences of an exogenous upsurge in coca prices and cultivation in Colombia, where most coca leaf is now harvested. This shift generated only modest economic gains in rural areas, primarily in the form of increased self-employment earnings and increased labor supply by teenage...

We develop semiparametric tests for conditional independence in time series models of causal effects. Our approach is motivated by empirical studies of monetary policy effects and is semiparametric in the sense that we model the process determining the distribution of treatment—the policy...