Using Greek high quality administrative data we show that class size has a hump shaped effect on achievement whereas most of the literature assumes linearity. We then embed our estimates for this relationship in dynamic structural model with costs hiring and firing. find sizes around 19 maximize attainment, existing result an average 22–23 being chosen. Firing are about same as consistent prese...

Objectives: This study sought to assess the relation of mandibular cortical index (MCI) with age, gender and gonial angle size in an Iranian adult population using digital panoramic radiography. Methods: We evaluated 370 digital panoramic radiographs of patients and divided them into five 10-year age groups. Each radiograph was assigned to low (≤120°) or high (≥125°) angle grou...