Catalonia has been removed from the latest PISA rankings after the OCDE ruled its results invalid because of a major breach of testing rules. More than 23% of students were left out of the assessment, almost five times the allowed limit, making the region’s scores unusable for comparison. Most of the excluded students had learning difficulties or lacked language skills, meaning Catalonia’s reported gains in science and reading cannot be trusted.
The Catalan Department of Education is still investigating how such a large error occurred during student selection for the 2025 PISA tests. Despite the setback, regional officials have played down its consequences, saying Catalonia already has enough data from its own diagnostic exams and those run by the central government. They argue that these local assessments are sufficient to judge the region’s education system, even though the OCDE’s decision leaves Catalonia out of international comparisons for this cycle.
The OCDE reported that Catalonia’s exclusion rate reached 23.2%, far above the 5% maximum and higher than Murcia’s 12.7%. Murcia’s results were retained but flagged with a warning, while Catalonia’s were left out of the basic OCDE report and appear only in Spanish data tables with a disclaimer. The agency made clear that these figures cannot be used to compare Catalonia with other regions or with previous years.
If the altered sample had been accepted, Catalonia would have scored 502 points in science, well above the Spanish average of 477 and the OCDE average of 482. In reading, the region would have reached 473, also above both national and international averages. But these figures are meaningless because the sample was skewed by the removal of weaker students. Catalonia’s 474 points in math were only slightly above its previous results, suggesting that a valid sample might have shown a drop.
PISA tests are held every three years for 15-year-olds in 91 countries and are widely regarded as the basic international benchmark for education. In Spain, about 30,000 students from 1,000 schools took part, with Catalonia using an expanded sample from 51 schools. The 2025 edition focused on science but also tested reading and math. Despite the resources spent, Catalonia’s results have been discarded, and the regional evaluation agency says it will not publish its usual detailed report. Raw data will be available to analysts, but there will be no official interpretation.
Catalan education authorities say that upcoming results from the Generalitat’s own diagnostic tests, as well as future international studies such as PIRLS and TIMSS, will make up for the loss of PISA data. This approach resembles other regional policy disputes, including Catalonia’s conditional stance on migrant child support reported earlier, where local control is prioritized over outside benchmarks.
The OCDE’s decision to exclude Catalonia from PISA removes the region’s ability to compare itself with Spain and the rest of the world. While local officials say internal assessments are enough, the lack of internationally recognized data weakens transparency and accountability. This episode highlights a reluctance within Catalonia’s education administration to face uncomfortable facts, relying instead on self-produced metrics. The OCDE’s message is clear: without strict standards, local data cannot replace international comparisons.
