Schoolchildren work in a classroom on the first day of the new school year after summer break in Savenay, France, September 4, 2023. (REUTERS/Stephane Mahe)

The Paris-based Organization for Economic Cooperation and Development said it had seen some of the steepest drops in performance since 2000 when it began its usually triennial tests of 15-year-olds reading, maths and science skills.

While more than half of the 81 countries surveyed saw declines, Germany, Iceland, the Netherlands, Norway and Poland saw particularly sharp drops in mathematics scores, the OECD said.

Countries that provided extra teacher support during COVID school closures scored better and results were generally better in places where easy teacher access for special help was high. Poorer results tended to be associated with higher rates of mobile phone use for leisure and where schools reported teacher shortages.

The OECD said the decline was not inevitable, pointing to Singapore, where students scored the highest in maths, reading and science, with results that suggested they were on average three to five years ahead of their OECD peers.