The debate on the effects of inclusive education keeps resurfacing, and too often it misses the point. People usually framed it in absolute terms. That is understandable. Everyone involved wants the best for children. The problem is that people rarely define “the best”. Inclusive education is then presented either as a moral duty that harms no one or as a well-intentioned experiment that comes at the expense of “the rest of the class”. That latter question deserves also attention. Everyone has a right to a good education. What does inclusion actually do to learning outcomes, motivation, and well-being?

A new and successful replication study by Aleksander Kocaj, published in Contemporary Educational Psychology, attempts to answer precisely that question, carefully and rigorously. Not with small samples, but with large-scale, representative data from German fourth-graders, and explicitly as a replication of an earlier study that I must admit I did not know. When I looked it up, I discovered it had only been published in German. And I will be honest: my German is more than a little rusty. Still, as you know, I am always pleased to see solid replication research. Such studies remain far too rare in education research, even though they are crucial for separating noise from robust patterns.

The core question of this study is therefore straightforward: do students without special educational needs differ in inclusive classrooms compared to students in classrooms without peers labelled SEN (special educational needs), in terms of achievement, motivation, and psychosocial functioning? The answer is nuanced.

First, the reassuring part. For reading, listening comprehension, motivation, social integration, and school satisfaction, the study finds no meaningful negative effects. Students without SEN perform broadly just as well in inclusive classrooms as their peers elsewhere. The same holds for their academic self-concept, enjoyment of learning, and engagement with school. Those who automatically equate inclusion with a poorer learning environment for “the rest of the class” will find little support for that view in this study.

The picture, however, is not entirely positive. In spelling and mathematics, students without SEN in inclusive classrooms score slightly lower on average. The effects are small, around −0.07 to −0.09, statistically significant but pedagogically limited. They signal no dramatic learning losses, but minor shifts that remain barely visible at the individual level. Even so, their consistency warrants attention, especially because they reappear in this replication. That matters, since inclusion was already more firmly embedded in Germany by the time this second study took place.

Importantly, no single group drives these small negative effects. They occur when classrooms include students with emotional or behavioural difficulties, as critics often claim, but they also appear, again very modestly, when students with learning disabilities are present. This weakens the convenient narrative that places “the problem” solely with behavioural difficulties.

What the study does not show matters just as much. It finds no evidence that high-achieving students suffer disproportionate disadvantages. It offers no indication that motivation or well-being systematically declines under inclusion. Nor does it support the idea that inclusion automatically produces a poorer classroom or school climate. Where differences do emerge, they remain small, context-dependent. And they depend closely on how schools actually implement inclusion.

The question “Does inclusion work?” is therefore too crude. A better question is: under what conditions, for whom, and with what kind of support? Inclusion is not a uniform intervention, but an organisational and pedagogical choice whose effects depend on instruction, support structures, classroom management, and teacher expectations. Without those conditions, inclusion remains fragile—for students with and without SEN alike.

What this new study mainly does is blunt the sharp edges of the debate. It confirms that inclusion is not a disaster scenario for students without SEN, but neither is it a free lunch or a walk in the park. The study does not focus on the organisational and professional demands placed on teachers, but the small performance declines observed in certain domains clearly warrant attention. They point to the need for sufficient support, expertise, and realistic expectations of what teachers can achieve in heterogeneous classrooms.

Put simply, inclusive education is not just a moral statement, nor merely a technocratic reform. It is a complex transformation that only works when it is pedagogically thoughtful and structurally supported.

Image: https://www.pexels.com/nl-nl/foto/spelen-kinderen-kids-aan-het-leren-8422255/