"This paper examines the properties of instrumental variables (IV) applied to models with essential heterogeneity, that is, models where responses to interventions are heterogeneous and agents adopt treatments (participate in programs) with at least partial knowledge of their idiosyncratic...

We present identification and estimation results for the "collective" model of labour supply in which there are discrete choices, censoring of hours and nonparticipation in employment. We derive the collective restrictions on labour supply functions and contrast them with restrictions implied by...

This paper considers the problem of making inferences about the effects of a program on multiple outcomes when the assignment of treatment status is imperfectly randomized. By imperfect randomization we mean that treatment status is reassigned after an initial randomization on the basis of...

This paper develops methods for evaluating marginal policy changes. We characterize how the effects of marginal policy changes depend on the direction of the policy change, and show that marginal policy effects are fundamentally easier to identify and to estimate than conventional treatment...

This chapter presents an economic approach to character and personality traits with an application to the study of virtue. Economists interpret psychological traits, including character traits and virtue, as strategies that shape responses to situations (actions) determined by underlying...

This paper examines the economic foundations of three criteria used for evaluating the costs and benefits of social programs. Some criteria do not consider the scale of programs or address the costs associated with programs that expand or contract the total government budget. A recent addition...