Some families had better odds than others, even though they'd scored identically.
En Girona, más de 350 familias comparten la misma puntuación en el proceso de admisión a escuelas infantiles municipales, pero no las mismas probabilidades de conseguir plaza. Roger Sanjaume, analista de datos, descubrió que el mecanismo de sorteo previsto para el 2 de junio producía variaciones de entre un 30 y un 40 por ciento en las posibilidades reales de cada familia, a pesar de su empate formal. En lugar de guardar ese hallazgo para sí, construyó una herramienta web con datos públicos para que cualquier familia pudiera conocer sus verdaderas probabilidades antes del sorteo. Es un acto pequeño con una pregunta grande detrás: ¿puede llamarse justo un sistema que trata igual en apariencia lo que no lo es en la práctica?
- Más de 350 familias de Girona llegan al sorteo del 2 de junio creyendo que compiten en igualdad de condiciones, pero la mecánica del sistema les otorga probabilidades radicalmente distintas sin que nadie se lo haya dicho.
- Un analista de datos detecta que la variación en las posibilidades reales entre solicitantes con idéntica puntuación puede alcanzar el 30 o el 40 por ciento, una brecha que el sistema nunca hizo visible.
- Sanjaume construye en respuesta una aplicación web que cruza los listados públicos de puntuación con las reglas del sorteo para devolver a cada familia su probabilidad individual y real.
- La herramienta convierte una opacidad estructural en información accionable: algunas familias descubrirán que sus opciones son mejores de lo que creían, otras que son peores, todas que el sorteo no era lo que parecía.
- La pregunta que queda abierta es si esta transparencia forzada obligará a Girona o a la administración autonómica a rediseñar un mecanismo de asignación que produce desigualdad donde promete azar puro.
Roger Sanjaume es analista de datos, y cuando la candidatura de su hija entró en el sorteo para una plaza en una escuela infantil municipal de Girona, hizo lo que hacen los analistas: miró los números con atención. Lo que encontró le incomodó. Más de 350 familias estaban empatadas a 30 puntos en el baremo de admisión, todas ellas a la espera de un sorteo fijado para el 2 de junio. Pero el sorteo, descubrió Sanjaume, no era tan igualitario como parecía. Dependiendo de la posición de cada solicitud en la cola, las probabilidades reales de conseguir plaza en la escuela preferida podían variar entre un 30 y un 40 por ciento. Una curiosidad matemática, la llamó él. Una anomalía estructural, podría llamarla cualquier otra persona.
En lugar de quedarse con ese conocimiento, Sanjaume construyó una herramienta. Usando únicamente datos públicos —los listados de puntuación y las reglas del propio mecanismo de sorteo— desarrolló una aplicación web que cualquier familia podía consultar para conocer sus probabilidades reales antes de que se celebrara el sorteo. No las probabilidades que el sistema daba a entender. Las probabilidades reales, calculadas a partir de cómo el sistema funciona de verdad.
Lo que la aplicación reveló es que el sistema de asignación de plazas en las escuelas infantiles de Girona contiene un fallo de diseño: las familias no compiten en igualdad de condiciones aunque tengan idéntica puntuación. El sorteo es aleatorio en su apariencia, pero no en su equidad. Algunas familias salen favorecidas por una peculiaridad matemática integrada en el mecanismo, no por mérito ni por necesidad.
Antes del 2 de junio, cualquier familia que quisiera podía saber exactamente dónde estaba parada. Lo que ocurra después depende de si esa visibilidad provoca algo: si los padres usan la herramienta, si la administración decide que un sorteo con variaciones de 30 a 40 puntos porcentuales entre solicitantes igualmente cualificados merece ser reformado. Sanjaume ha hecho lo que estaba en su mano: convertir lo invisible en visible. El resto le corresponde al sistema.
Roger Sanjaume is a data analyst by trade, which means he looks at numbers the way other people look at weather—as a system with patterns, probabilities, and hidden rules. When his daughter's name went into the lottery for a spot at a municipal preschool in Girona, he wasn't alone. More than 350 families in the city faced the same uncertainty, all of them tied at exactly 30 points in the admissions scoring system, all of them waiting for a draw scheduled for June 2nd to determine who would get in and who wouldn't.
But Sanjaume noticed something that bothered him. The lottery mechanism itself—the rules governing how names would be selected from that pool of equally qualified families—wasn't actually equal. It was a mathematical curiosity, he would later call it. Some families had better odds than others, even though they'd scored identically. The difference wasn't small. Depending on where your application sat in the queue, your chances could swing by as much as 30 to 40 percent.
So he did what made sense to him: he built a tool. Using publicly available data—the point lists and the lottery mechanism itself—Sanjaume created a web application that any family could use to calculate their actual probability of securing their first-choice school before the draw happened. It was transparency made functional. It was also, in a way, an indictment.
The application works from the ground up. You feed it the public information that already exists: the scoring lists, the rules of the lottery system. From there, it calculates what your individual odds really are. Not the odds everyone assumes they have. Not the false equality of a simple random draw. Your actual odds, based on how the system is actually constructed.
What Sanjaume had discovered, and what his tool now made visible to any parent willing to look, was that the Girona preschool allocation system contained a structural flaw. Families weren't competing on equal terms, even when they had equal scores. The lottery wasn't truly random in its fairness. It was random in appearance only.
The draw was set for June 2nd. By then, 350-plus families would know, if they chose to use Sanjaume's application, exactly where they stood. Some would see their chances were better than they'd assumed. Others would see they were worse. All of them would see that the system they'd been told was fair operated according to rules that favored some applicants over others—not because of merit or need, but because of a mathematical peculiarity baked into the mechanism itself.
What happens next depends on whether this visibility changes anything. Whether parents use the tool. Whether the city of Girona, or the regional government running these schools, decides that a lottery system that produces 30 to 40 percent variations in probability among equally qualified applicants needs to be redesigned. For now, Sanjaume has done what he could: he's made the invisible visible. The rest is up to the system.
Citações Notáveis
By a mathematical curiosity, not all families have the same opportunities in the lottery draw— Roger Sanjaume, data analyst
A Conversa do Hearth Outra perspectiva sobre a história
Why did you decide to build this tool instead of just noting the problem and moving on?
Because my daughter was in that lottery. Because 350 other families were too. Once you see an inequality like that, you can't unsee it. And if you have the skills to make it visible, you have to.
Did you expect the variations to be that large—30 to 40 percent?
Honestly, I suspected something was off, but the magnitude surprised me. That's not a rounding error. That's a structural problem.
Do you think the city knew about this?
The data is public. The mechanism is public. So either they knew and didn't care, or they didn't look closely enough. Either way, the families deserved to know.
What do you hope happens now that the tool exists?
At minimum, that people use it and understand their real odds. Beyond that—that someone in government asks whether this system should exist at all, or whether it needs to be rebuilt from scratch.
Are you worried about backlash?
I'm a data analyst. I'm just showing what the numbers say. If that's controversial, that tells you something about how we've been handling this.