The true effect of students’ employment on the duration of studies

We examine the effect of the first-degree students’ employment on the prolongation of their studies. When employing a popular instrumental variable, the regional unemployment rate, we find a negative impact of students’ employment on duration of studies. Then, adding a predetermined IV–the individual’s employment prior to the beginning of academic studies–turns the estimate positive. Furthermore, we find that the relationship between the extent of students’ employment and duration of their studies depends on their age: among the younger students (aged 22–26), the extent of employment has no effect on the duration of studies, while among the older students, the effect is positive and statistically significant.