No single indicator explains the whole reality: GDP does not summarize a country's well-being; unemployment does not describe the entire labor market. But no one would stop measuring unemployment because it is an imperfect statistic. The value of an indicator is not to be perfect, but to allow us to see if we are advancing or regressing, and, from there, to decide. That is why the tools that measure reality are a governance infrastructure. PISA tests are one of them. And this week we have learned that Catalonia has lost the possibility of comparing its 2025 results with those of other countries and the past.PISA has known limitations. It neither measures everything that matters in school nor does everything it measures depend exclusively on what students know. But these limitations do not nullify the value of comparison. Precisely because they remain stable from one edition to another, the value of PISA is not a snapshot of a single year, but rather the ability to know if an educational system improves or deteriorates over time. And a trend can only be interpreted if all the snapshots have been taken with the same criteria.Well, this time comparability has gone out the window. The OECD allows for the exclusion of some students in very specific situations, such as certain disabilities or a very recent enrollment without language proficiency, but it sets a ceiling: a maximum of 5%. In Catalonia, 23% have been excluded, almost five times more. But the irregularity is not excluding anyone; what breaks the sample is having done it massively and without anyone checking. There's no need for bad faith: it is enough not to supervise. And the result is that Catalonia has lost precisely what made the test valuable: the possibility of rigorously comparing itself with its past and with others.

The Catalan PISA fiasco is not just a statistical error. It is an educational paradox. When almost one in every four selected students is left out of a test that is supposed to portray the system, the problem is not only that the sample ceases to be reliable. The problem is what this exclusion reveals about our way of understanding inclusion.An inclusive school cannot demonstrate its inclusion by excluding from evaluation the students who most reveal their limits.Catalonia has participated in PISA for years, and the Administration was aware of the criteria, the procedure, and the importance of preserving the representativeness of the sample. It is not enough to talk about a confusion: it must be explained why no control mechanism stopped a deviation of this magnitude. There are, of course, exceptional cases where a student cannot take a test like PISA under valid conditions. But when the exception extends to leaving out almost a quarter of the sample, we are no longer just talking about a technical problem. We are talking about a diagnosis that has ceased to represent the classrooms it intended to evaluate.Students with cognitive, emotional, behavioral, or linguistic difficulties are not an anomaly of the system. They are the system. We cannot consider them fully included if they stop being counted when we evaluate what the school achieves. A common confusion arises here: confusing inclusion with protection. Protecting a student from a situation they truly cannot face may be necessary. But interpreting difficulties too broadly as a reason not to assess them is another matter. It may seem compassionate, but it can lower expectations and avoid the more uncomfortable question: what has this student learned and what has the system failed to offer them? Stopping the questions is not inclusion. What is not evaluated does not disappear. It simply stops engaging us. If the most vulnerable students are left out of the sample, the picture may be more comfortable, but it is less honest. It no longer explains what the school is doing with the student body as a whole, but only with those we have considered more easily assessable.

Jesús Moral (1959, Còrdova) is a mathematics professor and has worked for almost two decades in the Department of Education. He has been head of the Center Organization service, secretary of the School Council of Catalonia, secretary of the Higher Council for the Evaluation of the Educational System, and deputy director general of Innovation and Training. In 2018, he was part of the department's team responsible for organizing the PISA tests. In a conversation with ARA, he analyzes the error that has invalidated the inclusion of Catalonia's results in the international tests and which, therefore, makes it impossible to compare the level of Catalan students with that of other territories and with previous years.

The Minister of Education, Esther Niubó, is appearing this afternoon in Parliament to explain the Generalitat's incredible failure to organize the PISA tests. As we know, the story could not be more lamentable, no matter how you look at it: the OECD warned in March. No information was given until July, until a Friday at the end of July, to be exact, when they sent a director general to face the music and not the minister, and they describe an error in the sample of students examined, which far exceeds any explainable decimal error, as a specific and technical problem.As we explain today, the alteration of the PISA sample in Catalonia far exceeds that of any country in the latest report. It reminded me of the day when the Generalitat, under the presidency of Pere Aragonès, did not know how to correctly convene a competitive examination. With the difference that this PISA issue is an international embarrassment. And I prefer to believe it was a (serious) fiasco rather than have to think it's a way to circumvent results that will be poor given the problems that have been affecting Education in Catalonia for years. It is enough to remember that we finished the course amidst strikes and we will start it the same way. The problem with Education is in the classrooms, which are a reflection of all of society's problems, in the training of teachers, in the authority of principals, in the tension of an inclusive school that lacks the means to be worthy of the name, in a Catalonia that has been getting poorer, etc. But something is happening in the Department of Education and, by extension, in the Government, when it signs a union pact that inflames the unions, closes an agreement with the OECD to improve teaching, and, one year later, makes a big mistake in the sample for the PISA tests. And in another order of indignation, we have the multitudinous demonstration yesterday in Palma de Mallorca against the excess of tourism that has led the island, like the rest of the Balearic Islands, to collapse. There is no need for many explanations as to why the protest, because in Catalonia we know well what tourist collapse is, which affects ecology, mobility, housing, culture, language, etc. The manifesto of the call has a quite explicit paragraph on the effect of tourism: “It invaded our coasts, then our towns and our cities and is currently occupying our homes. Mallorca cannot fit any more hotels, cannot fit any more coffee franchises, fast food or cheesecakes, and cannot fit any more tourists! Mallorca at its limit! Less tourism, more life!” Such a demonstration is a sign that must be listened to and attended to with urgency. But everything suggests that it will not be so, for now, because the Balearic government and tourist interests are one. The proof is what happened in the end:

Everyone remembers how The PISA tests revealed the low level of our students in mathematics or reading comprehension. These tests also revealed a low level in science, but few talk about this, even though Catalan students' knowledge of biology, technology, and earth sciences is eight points below the Spanish average and that of OECD countries. In this same vein, the basic skills tests administered by the Generalitat (Catalan government) in sixth grade show that science receives the worst scores of all subjects. In the last year evaluated, 2025, science is the only subject with a failing grade. No other subject has such poor results. Catalan children know more English than physics or geology.