In many fields researchers wish to consider statistical models that allow for more complex relationships than can be inferred using only cross-sectional data. Panel or longitudinal data where the same units are observed repeatedly at different points in time can often provide the richer data...

With panel data important issues can be resolved that can not beaddressed with cross--sectional data. A major drawback is that paneldata suffer from more severe missing data problems. Adding a sampleconsisting of new units randomly drawn from the original populationas replacements for units who...

This paper presents an analysis of the failure and completion rates of graduate students in economics at three universities in The Netherlands. We find that an indicator of the research productivity of the supervisor is an important determinant of the completion and dropout rates. However, this...