Mean years of schooling


Average number of completed years of education of a country's population aged 25 years and older, excluding years spent repeating individual grades.

Data source

National population censuses, household or labour force surveys.

Source definition

UIS Methodology for Estimation of Mean Years of Schooling.

Data required

Population aged 25 years and above by highest level of education attained.


In general, the indicator’s value denotes the level of skills and competencies of a country's population, which could be seen as a proxy of both the quantitative and qualitative aspects of the stock of human capital. A relative high value indicates great shares of the adult population according to the highest level of education attained or completed, and reflects a performing educational system.


Caution is required when using this indicator for cross-country comparison. Countries do not always classify degrees and qualifications at the same ISCED levels, even if they are received at roughly the same age or after a similar number of years of schooling. Also, certain educational programmes and study courses cannot be easily classified according to ISCED levels. It is also important to note that this indicator is based on education levels attained or completed, in terms of years of schooling, and do not necessarily reveal the quality of the education (e.g. learning achievement or other outcomes).


The indicator reflects the level of schooling of the population aged 25 years and above, hence the stock and quality of human capital within a country, so as to gauge needs and establish policies for upgrading it. This indicator also informs about the performance of the education system and its accumulated impact on human capital formation.

Quality standards

This indicator should be based on complete and reliable census or survey data on the adult population, applying clear classification of levels of education attained or completed in accordance with the International Standard Classification of Education (ISCED).

The UIS is the custodian agency for ISCED. It develops questionnaires and quality control protocols for country data reporting, and maintains the global database on the structure of education, the official duration of each level of education, and the educational attainment data. The United Nations Population Division (UNPD) produces and maintains population data. National population data that comply with UIS quality standards can also be used.

Types of disaggregation

By sex.