Catalonia's 2025 PISA results invalidated after sampling error

The Catalan Department of Education confirmed that a technical incident in the sample selection for the 2025 PISA assessment means the results cannot be compared with other Spanish regions or with previous years.

The error stemmed from an exemption rate of 23.2 % of the 2,545 pupils slated to take the test, far above the OECD‑recommended ceiling of 5 %. In total 591 students were excluded, compromising the statistical representativity of the sample.

In response, the regional government launched internal investigations, created a new Coordination Commission for evaluation studies, and faced criticism from opposition parties and the teachers’ union USTEC, which accused officials of withholding the problem for months and called for an independent audit.