The question of whether two drugs – namely alcohol and tobacco – are used as complements or substitutes is of crucial interest if side-effects of anti-smoking policies are considered. Numerous papers have empirically addressed this issue by estimating demand systems for alcohol and tobacco...

We analyze demand for prepaid cellular voice and short message service (SMS) in South Africa by means of a demand-and-supply structural model based on a multinomial specification fitted to a cross-sectional data set on Vodacom customers collected in 2005. We find that consumers are very...

This paper formulates a structural empirical model of heterogeneous firms whose workers exhibit fair-wage preferences. In the underlying theoretical framework, such preferences lead to a link between a firm's operating profits on the one hand and wages of workers employed by this firm on the...

For many students throughout the world the time to obtain an academic degree extends beyond the normal completion time while college tuition is typically constant during the years of enrollment. In particular, it does not increase when a student remains in a program beyond the normal completion...

In many countries, caseworkers in a public employment office have the dual roles of counselling and monitoring unemployed persons. These roles often conflict with each other leading to important case-worker heterogeneity: Some consider providing services to their clients and satisfying their...

This paper compares the predictive ability of the factor models of Stock and Watson (2002) and Forni, Hallin, Lippi, and Reichlin (2005) using a large panel of US macroeconomic variables. We propose a nesting procedure of comparison that clarifies and partially overturns the results of similar...

In a large class of hazard models with proportional unobserved heterogeneity, the distribution of the heterogeneity among survivors converges to a gamma distribution. This convergence is often rapid. We derive this result as a general result for exponential mixtures and explore its implications...

Instrumental variable estimation requires untestable exclusion restrictions. With policy effects on individual outcomes, there is typically a time interval between the moment the agent realizes that he may be exposed to the policy and the actual exposure or the announcement of the actual...

The Swedish adult education program known as the Knowledge Lift (1997--2002) was unprecedented in its size and scope, aiming to raise the skill level of large numbers of low-skill workers. This paper evaluates the potential effects of this program on aggregate labour market outcomes. This is...

This paper studies whether structural properties of friendship networks affect individual outcomes in education. We first develop a model that shows that, at the Nash equilibrium, the outcome of each individual embedded in a network is proportional to her Katz-Bonacich centrality measure. This...