When event data are retrospectively reported, more temporally distal events tend to get “heaped” on even multiples of reporting units. Heaping may introduce a type of attenuation bias because it causes researchers to mismatch time-varying right-hand side variables. We develop a model-based...

In this paper we propose a method to estimate models in which an endogenous dichotomous treatment affects a count outcome in the presence of either sample selection or endogenous participation using maximum simulated likelihood. We allow for the treatment to have an effect on both the sample...

This paper studies the determinants of the use of different strategies by mobile-users for reducing their spending. This empirical exercise is done with a special survey focused in lowincome people from developing countries such as Argentina, Brazil, Colombia, Mexico, and Peru. Our methodology...

The German health care reform of 1997 provides a natural experiment for evaluating the price sensitivity of demand for physicians’ services. As part of the reform, copayments for prescription drugs were increased by up to 200 percent. However, certain groups of people were exempted from the...

The paper evaluates the German health care reform of 1997, using the individual number of doctor visits as outcome measure and data from the German Socio- Economic Panel for the years 1995-1999. A number of modified count data models allow to estimate the effect of the reform in different parts...