Typology of out-of-school children. Primary. Never in school. Quintile 2 is the percentage of quintile 2 out-of-school primary-school-age children who have never attended school and are not likely to enter school in the future. Since no survey can say definitively that a school-age person will never attend school, this is a probabilistic indicator. The indicator is based on UNESCO’s methodology, which estimates the proportion of children who will never attend school as the proportion of out of school for the age group with the lowest proportion of out-of-school children. This methodology assumes no dropout before the age at which enrolment rates peak, and no late entry after the age with peak enrolment. Each poverty quintile represents one fifth of students with quintile 1 being the poorest 20 percent of students and quintile 5 being the richest 20 percent of students.