Next year's Programme for International Student Assessment (Pisa) has been postponed until 2022 because of the coronavirus crisis.
An Organisation for Economic Co-operation and Development spokesperson said that, owing to the Covid-19 crisis, "OECD member countries have decided to postpone the next two Pisa surveys".
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Students are now due to take the test in 2022, with results published in December 2023. The following Pisa survey will then be published in 2026, not 2025.
Pisa is an international test of 15-year-olds and has come to be known as the world's most influential education study. In 2018, 600,000 students from 79 countries took part in the assessment, representing 37 OECD countries and 42 partner countries.