Education at a Glance 2016
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Education at a Glance 2016

OECD Indicators

Education at a Glance is the authoritative source for information on the state of education around the world. It provides key information on the output of educational institutions; the impact of learning across countries; the financial and human resources invested in education; access, participation and progression in education; and the learning environment and organisation of schools.

The 2016 edition introduces a new indicator on the completion rate of tertiary students and another one on school leaders. It provides more trend data and analysis on diverse topics, such as: teachers’ salaries; graduation rates; expenditure on education; enrolment rates; young adults who are neither employed nor in education or training; class size; and teaching hours. The publication examines gender imbalance in education and the profile of students who attend, and graduate from, vocational education.

The report covers all 35 OECD countries and a number of partner countries (Argentina, Brazil, China, Colombia, Costa Rica, India, Indonesia, Lithuania, the Russian Federation, Saudi Arabia and South Africa).

This edition includes more than 125 figures and 145 tables. The Excel™ spreadsheets used to create them are available via the StatLinks provided throughout the publication. More data is available in the OECD Education Statistics database.

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Indicator D2 What is the Student-Teacher Ratio and How Big are Classes? You do not have access to this content

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Indicator D2 shows the average class size in primary and lower secondary education (broken down by general and vocational programme), the ratio of students to teachers by type of institution (public, government-dependent private and independent private), and examines the relationship between class size and student learning.

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Chapter Highlights

  • The average primary school class in OECD countries has 21 students, and this average increases to 23 in lower secondary education. These figures represent a decrease when compared to the OECD average class sizes in 2005.

  • The difference in average class size between public and private institutions in primary education varies substantially across OECD countries, but is considerably larger in partner countries.

  • There are 15 students per teacher in primary education, on average across OECD countries. The figure increases to 17 students per teacher, on average, at the tertiary level.

Figure D2.1. Average class size, by level of education (2014)

Countries are ranked in descending order of the average class size in lower secondary education.

Source: OECD. Table D2.1. See Annex 3 for notes (

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Class size and student-teacher ratios are much-discussed aspects of education and, along with students’ instruction time (see Indicator D1), teachers’ working time (see Indicator D4), and the division of teachers’ time between teaching and other duties, are among the determinants of the demand for teachers. Together with teachers’ salaries (see Indicator D3) and the age distribution of teachers (see Indicator D5), class size and student-teacher ratios also have a considerable impact on the level of current expenditure on education (see Indicators B6 and B7).

Smaller classes are often seen as beneficial because they allow teachers to focus more on the needs of individual students and reduce the amount of class time needed to deal with disruptions. Yet, while there is some evidence that smaller classes may benefit specific groups of students, such as those from disadvantaged backgrounds (Piketty and Valdenaire, 2006), overall, evidence of the effect of differences in class size on student performance is weak.

The ratio of students to teaching staff indicates how resources for education are allocated. Smaller student-teacher ratios often have to be weighed against higher salaries for teachers, investing in their professional development, greater investment in teaching technology, or more widespread use of assistant teachers and other paraprofessionals, whose salaries are often considerably lower than those of qualified teachers.

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  • With the exceptions of Chile, Colombia, Luxembourg and Mexico, the student-teacher ratio decreases or stays the same between primary and lower secondary levels in all countries with available data, despite a general increase in class size between these levels.

  • On average across OECD countries, the student-teacher ratio in lower and upper secondary education is slightly lower in private institutions than in public institutions. This is most striking in Mexico where, at the secondary level, there are at least 14 more students per teacher in public institutions than in private institutions.

  • Class size varies significantly across countries. The biggest classes in primary education are observed in Chile (30 students per classroom) and China (37 students), while in Latvia, Lithuania and Luxembourg, classes have fewer than 17 students, on average.

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