Teacher shortages have become a persistent problem in many countries. But at the same time, birth rates are falling in many of those same countries. Fewer children mean fewer students. And fewer students mean we may need fewer teachers, and so surely this will mean that teacher shortages should eventually disappear, at least partially, on their own? Not so fast..

It turns out not to be that simple. That is one of the interesting, yet simultaneously depressing, messages from the new Education at a Glance 2026 by the OECD . This edition pays close attention to teacher shortages and links them to the demographic changes facing education in the coming years.

The changes are more than significant. For instance, the OECD expects the number of children aged 5 to 14 in OECD countries to decline by 9 per cent between 2024 and 2033. I do not know if we have experienced such a contraction in recent history. In theory, this should give education systems quite a bit of breathing room. After all, fewer pupils means that you can create smaller classes with the same number of teachers, or… that you need fewer teachers.

However, recent years have apparently taught us that education systems do not work so ‘mechanically’. The OECD looked at what happened in countries where the number of pupils had already declined. They noticed that the number of teachers and the number of classes did not always decrease proportionally. In some countries, the number of teachers or classes even increased even as the number of pupils decreased.

But there is more, and that is the counterpart to the youth population: precisely, the ageing population. While the number of pupils is declining, many teachers are also leaving the education system. A quarter of secondary school teachers in OECD countries are now 55 years or older. Consequently, a significant portion of the current teaching staff will reach retirement age in the coming years. Fewer pupils therefore certainly means that fewer teachers may be needed, but that is different from saying that there will automatically be enough teachers available.

Reading these insights immediately made me think of the Netherlands. This country beautifully illustrates how both movements can occur simultaneously. According to the Dutch Reference Projection 2026, the total number of pupils and students will decrease from approximately 3.64 million in 2025 to 3.48 million in 2034, a decline of 4.4 per cent. TThe OESCD doesn’t expext to see again some growth until after that. The precise turning point varies significantly by education sector. Growth is expected again in primary education starting in 2034, while in secondary education it is not expected until 2040.

This naturally has consequences for the demand for teachers. For example, the Dutch Teacher Labour Market Trend Report 2025 predicts that nearly 5 per cent fewer FTE teachers will be needed in secondary education in 2034 than in 2024. In vocational education, the figure is even higher, at over 5 per cent. Looking back, one might think: problem solved.

But at the same time, teachers are leaving the education system. The main reason is retirement. To replace them, a new influx is needed. Both primary and secondary education are heavily dependent on graduates from teacher training programs. When this influx is insufficient, unfilled vacancies still arise despite the decreased need for teachers. Loosely translated, the teacher shortage can then persist.

It is therefore perfectly possible that these two sentences can be true at the same time:

• We will need fewer teachers in the future.
• We will still have too few teachers in the future.

Suppose, very simply, that an education system needs 100 teachers today but can only find 95. Due to declining student numbers, only 95 teachers will be needed in ten years. But if, in the meantime, only 90 teachers are available due to retirement and insufficient intake in teacher training programs, the need has decreased, and there is still a shortage.

The OECD also describes a second possible problem. Teachers are not simply interchangeable units that one can move without difficulty to where you need them. Teacher shortages can therefore vary significantly by region, school, and subject. E.g. the OECD observes shortages particularly in mathematics and science, but less frequently in subjects such as the arts, social sciences, and physical education.

Also, the student population in one region may shrink faster than in another. A surplus of a certain type of teacher for a specific subject area in one place does not automatically resolve a shortage of another type of teacher in another region. This results in demographic development ultimately remaining primarily a matter of distribution.

The OECD does not view the expected decline in the number of pupils as an automatic solution. The organisation does see it as a potential opportunity. Education systems could use the freed-up capacity to redistribute teachers and resources to schools, regions, and subject areas with the greatest shortages. And then you immediately realise the Achilles’ heel of this reasoning. Those teachers would have to be willing to do so. And I know for sure that will not be that easy.