International comparative studies of student performance have initiated political discussions in countries all over the world on how to improve the educational achievement of students. The empirical evidence suggests that central exams help to achieve higher student performance. Central exams...

The role of friends in the US opioid epidemic is examined. Using data from the National Longitudinal Survey of Adolescent Health (Add Health), adults aged 25-34 and their high school best friends are focused on. An instrumental variable technique is employed to estimate peer effects in opioid...