Catalonia's Student Exclusions Undermine PISA Results

In the 2025 Programme for International Student Assessment (PISA), Catalonia excluded 23% of the 2,545 selected 15‑year‑olds from the test, far above the OECD‑set maximum of 5% needed for statistical validity. The OECD therefore deemed the Catalan data inadmissible and removed the region’s results from the international report scheduled for release on 8 September. The excess exclusions were first flagged by the testing contractor 2E Estudios y Evaluaciones, which warned the Spanish Ministry of Education of unusually high exclusion rates. Ambiguous instructions given to school directors about which pupils could be excluded led to inconsistent practices – one director excluded 13% of pupils, another only 3.6%. Although the Ministry and the Catalan government (Generalitat) were aware of the problem, they did not disclose it until late March 2026, when the OECD discussed the data with Spanish officials. The episode leaves a gap in the national statistics and means Catalan results cannot be compared with other regions or previous PISA cycles.