In 2022 the international test of 15-year-olds represented only 36% of teenagers in Cambodia and 68% in Vietnam
The rest are out of school or below grade 7. In Finland the sample represents 95% of 15-year-olds. A high score with low coverage is the score of those still in school.
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The test is taken by pupils, not by all teenagers. Where many leave school early, it sees only those who stayed, usually the stronger ones.
Each bar is the share of all the country's 15-year-olds the test sample represents: the six lowest, with Vietnam, Mexico and Finland for comparison.
- Cambodia: coverage of 15-year-olds, 2022 %
36
- Ukraine: coverage of 15-year-olds, 2022 %
42
- Guatemala: coverage of 15-year-olds, 2022 %
48
- Panama: coverage of 15-year-olds, 2022 %
58
- Jamaica: coverage of 15-year-olds, 2022 %
58
- El Salvador: coverage of 15-year-olds, 2022 %
61
- Mexico: coverage of 15-year-olds, 2022 %
64
- Vietnam: coverage of 15-year-olds, 2022 %
68
- Finland: coverage of 15-year-olds, 2022 %
95
OECD PISA 2022, table I.A2.1: coverage index 3, the weighted sample as a share of the country's whole 15-year-old population.
Values above 100% happen when the population estimate is off. As enrolment rises, comparing a country's scores over time partly compares different parts of a generation.
A question for this picture
How has Vietnam's maths score changed?