Spain's Catalonia excludes 23% of its students from PISA

Catalonia leaves one in four students out of PISA

The PISA 2025 report has revealed an unprecedented grievance. Catalonia excluded 23% of its students from the sample, all of them with learning difficulties, when the OECD sets the limit at 5%. The other Spanish regions, with percentages ranging from 2% to 5%, maintain that they handled the exclusion index "rigorously" and "under control". Regional education minister Esther Niubó has already appeared before the Catalan Parliament, but the hole is hard to plug.

A manoeuvre that inflates the averages

Excluding struggling or disruptive students is not a technical detail: it is the most direct way to raise the average score. Every student left out was a statistical drag. That is why the OECD caps exclusions at 5%: to keep the results comparable. Catalonia has multiplied that figure more than fourfold, and that cannot be fixed with a parliamentary appearance.

The demographic factor nobody mentions

In any analysis of the results, an uncomfortable correlation always looms: regions with a lower proportion of immigrants and no co-official language tend to score higher. Castilla y León and Asturias, with a 2% exclusion rate, have led the rankings for years. That explains part of the gap, but it does not justify the manipulation. In Asian countries, moreover, entire schools are selected to doctor the results, turning PISA into a mirror everyone looks into but nobody wants to see themselves in.

With 23% on the table, the question is straightforward: what is the point of a report that trims out those who fail? Very little, other than pretending to be what one is not.

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