School life expectancy


Number of years a person of school entrance age can expect to spend within the specified level of education.

Data source

School register, school survey or census for data on enrolment by age; population census and estimates for school-age population.

Source definition

UNESCO Institute for Statistics

Calculation method

For a child of a certain age a, the school life expectancy is calculated as the sum of the age specific enrolment rates for the levels of education specified. The part of the enrolment that is not distributed by age is divided by the school-age population for the level of education they are enrolled in, and multiplied by the duration of that level of education. The result is then added to the sum of the age-specific enrolment rates.

Data required

Enrolment by age and of age unknown at all levels of education; population by single years of age; or, alternatively, the age-specific enrolment ratios for all levels of education.


A relatively high SLE indicates greater probability for children to spend more years in education and higher overall retention within the education system. It must be noted that the expected number of years does not necessarily coincide with the expected number of grades of education completed, because of repetition. Since school life expectancy is an average based on participation in different levels of education, the expected number of years of schooling may be pulled down by the magnitude of children who never go to school. Those children who are in school may benefit from many more years of education than the average.


Caution is required when making cross-country comparisons; neither the length of the school year nor the quality of education is necessarily the same in each country. In addition, as this indicator does not directly take into account the effects of repetition, it is not strictly comparable between countries with automatic promotion and those allowing grade repetition. It should also be noted that, depending on countries, the enrolment data do not account for many types of continuing education and training. For these reasons, this indicator should be interpreted in the light of complementary indicators, particularly percentage of repeaters.


To show the overall level of development of an educational system in terms of the average number of years of schooling that the education system offers to the eligible population, including those who never enter school.

Quality standards

Requires complete and reliable data on enrolment and population by single-years of age corresponding to all levels of education for the entire duration of schooling, including tertiary education.

Types of disaggregation

By level of education and by sex.