A repeater is defined as a pupil who is not promoted to the next grade or does not complete an educational programme and who remains in the same grade the following school year (UIS, 2012: 17).
Repetition can result from academic failure, unsatisfactory progress, insufficient examination marks to advance to the next level of instruction, age, poor attendance or, simply, from lack of local educational opportunities. It may be obligatory or, in the case of some more developed countries, it may require the agreement of the student and/or parents.
UIS. 2012. Global education digest, 2012: opportunities lost: the impact of grade repetition and early school leaving. Montreal: UIS.