The number of pupils under the authority of one teacher in one classroom. Class sizes can be evaluated through the analysis of pupils-teacher ratio (PTR), the proportion of teachers in a school compared to the number of pupils studying. When the PTR is low, it means there is a sufficient number of teachers per class, on the contrary, when the ratio is high, there are not enough pupils for the number of teachers available.
UNESCO-BREDA (UNESCO’s Regional Bureau for Education in Africa). 2009. Universal primary education in Africa: The teacher challenge. Dakar: UNESCO-BREDA. Retrieved from: http://uis.unesco.org/sites/default/files/documents/universal-primary-education-in-africa-the-teacher-challenge-en.pdf