Average years of schooling

Description: Average years of formal education for individuals aged 15-64.
Data source: Barro and Lee (2015); Lee and Lee (2016) – with major processing by Our World in Data
Unit: years
Date range: 1870-2040
Last updated: 2023-07-17
Managed by: Tuna Acisu

For the years leading up to 2015, the data are derived from historical estimates, providing a retrospective view of education levels. For the years 2015 and beyond, the projections are grounded in the historical data of 2010, which serve as the foundational benchmark. These forward-looking projections are then crafted by analyzing trends in school enrollment and changes in population structures. These trends are informed by forecasts from the United Nations, ensuring a global perspective and understanding of future educational developments.
The method to estimate average years of schooling takes into account the age distribution in the population. This is important because access to education can vary significantly across generations. Older generations may have had fewer educational opportunities than younger ones, which affects the overall average education level.

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It also considers the typical duration required to complete each education level. For instance, primary education usually takes about 6 years, secondary education 4-6 years, and higher education may take even longer. Understanding the time investment required for different education levels is essential for accurate assessment.
At its core, the method calculates the average years of schooling. This is achieved by determining the percentage of the population that has completed each education level and multiplying it by the duration of that level. The sum of these results gives a comprehensive view of both the extent of educational attainment and the time spent in education by the population.
The method is dynamic, adapting to changes over time and across regions. For example, if a country increases the length of primary education, this change is included in subsequent calculations. This adaptability ensures that the average years of education remain relevant and accurate over time and across different educational systems.
Note that the method does not take into account the quality of education. It only considers the number of years spent in education. This means that the average years of schooling may not reflect the actual skills and knowledge of the population.

Frequently asked questions

How did Our World in Data process this data?

All data and visualizations on Our World in Data rely on data sourced from one or several original data providers. Preparing this original data involves several processing steps. Depending on the data, this can include standardizing country names and world region definitions, converting units, calculating derived indicators such as per capita measures, as well as adding or adapting metadata such as the name or the description given to an indicator.

At the link below you can find a detailed description of the structure of our data pipeline, including links to all the code used to prepare data across Our World in Data.

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Notes on our processing step for this indicator

Historical data up to the year 2010 has been sourced from 'Human Capital in the Long Run' by Lee and Lee (2016). This historical data was then combined with recent projections provided by Barro ane Lee (2015).

Regional aggregates were computed by Our World in Data through yearly population-weighted averages, where annual values are proportionally adjusted to emphasize the influence of larger populations.

Data sources

Barro and Lee – Projections of Educational Attainment

Using the estimates on school enrollment and population structure, Barro and Lee have constructed projections of educational attainment for the population, disaggregated by gender and age group (15–24, 25–64, and 15–64) for 146 countries from 2015 to 2040 at five-year intervals.

They first use the 2010 data on educational attainment by age group as benchmark figures to project the educational attainment of the population by age group for the next three decades. They then estimate the distribution of educational attainment for the younger population, aged 15-24, at the five-year intervals from 2015 to 2040 and then forward-extrapolate the estimates to construct the distribution of educational attainment for the older population groups. For the population structure, they use existing U.N. projections. For the detailed explanation of the estimation method, see Barro and Lee (2015, chapter 3).

Retrieved on

November 20, 2023

Retrieved from

http://www.barrolee.com/

Citation

This is the citation of the original data obtained from the source, prior to any processing or adaptation by Our World in Data.

Barro, Robert J. and Jong-Wha Lee, Education Matters: Global Schooling Gains from the 19th to the 21st Century (Oxford University Press, 2015)

Lee and Lee – Human Capital in the Long Run

Datasets on estimated school enrollment ratios from 1820 to 2010 and estimated educational attainment for the total, female, and male populations from 1870 to 2010. The estimates are available in five-year intervals for 111 countries.

Datasets were last updated in 2021 September. The research provides insightful analysis on the progression and trends of educational attainment over a long historical period, offering a comprehensive understanding of educational developments globally.

Retrieved on

November 20, 2023

Retrieved from

https://barrolee.github.io/BarroLeeDataSet/DataLeeLee.html

Citation

This is the citation of the original data obtained from the source, prior to any processing or adaptation by Our World in Data.

Lee, Jong-Wha and Hanol Lee, 2016, “Human Capital in the Long Run,” Journal of Development Economics, vol. 122, pp. 147-169.

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How to cite this page

To cite this page overall, including any descriptions, FAQs or explanations of the data authored by Our World in Data, please use the following citation:

“Data Page: Average years of schooling”, part of the following publication: Hannah Ritchie, Veronika Samborska, Esteban Ortiz-Ospina, and Max Roser (2023) - “Global Education”. Data adapted from Barro and Lee, Lee and Lee. Retrieved from https://archive.ourworldindata.org/20261014-113329/grapher/mean-years-of-schooling-long-run.html [online resource] (archived on October 14, 2026).

How to cite this data

If you have limited space (e.g. in data visualizations), you can use this abbreviated in-line citation:

Barro and Lee (2015); Lee and Lee (2016) – with major processing by Our World in Data

Full citation

Barro and Lee (2015); Lee and Lee (2016) – with major processing by Our World in Data. “Average years of schooling” [dataset]. Barro and Lee, “Projections of Educational Attainment”; Lee and Lee, “Human Capital in the Long Run” [original data]. Retrieved October 14, 2026 from https://archive.ourworldindata.org/20261014-113329/grapher/mean-years-of-schooling-long-run.html (archived on October 14, 2026).

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