In discussions about effective math education, opinions often run high. Sometimes they reach the point of heated debates, known as “math wars.” The question of explicit instruction vs constructivist teaching in mathematics is central to these discussions. Should we primarily let children discover things for themselves, through discussion and collaboration? Or does it work better if the teacher clearly demonstrates and guides them step by step? A new French study (Guilmois, Rohmer & Popa-Roch, 2025) provides engaging and stimulating evidence for this—and also food for thought.

The researchers compared two approaches in 24 classrooms (grade 4) and 17 classrooms (grade 7): socio-constructivist teaching and explicit direct instruction. The studies were conducted in schools within the so-called priority education networks in Martinique, where socio-economic challenges are significant. In short, a setting where the difference that good teaching can make can be noticeable.

A clear win for explicit instruction

The results leave little doubt: all children made progress, but those who received explicit instruction made significantly more progress. These were substantial effects. Especially for younger children, explicit instruction in subtraction also appeared to narrow the gap between weaker and stronger students. This was a finding we had already observed in a previous study. With older students, we observed progress in all the concepts related to “area.” However, the gap remained wider.

These are encouraging findings. They also align with previous meta-analyses. These show that explicit instruction—when properly implemented—is often the most efficient way to acquire basic knowledge and skills, especially for students at risk of falling behind. At a time when many children are globally underperforming in math (consider PISA and TIMSS), this is a notable achievement.

Why we should remain cautious

At the same time, caution is advised. The researchers themselves rightly point out that there are always factors at play that cannot be fully controlled: the teacher’s experience, classroom dynamics, and the school context. Moreover, these are relatively short interventions, where the immediate effects were examined. Whether the gains are sustained in the long term was not discussed in this study. And there is always the question of generalizability: Does this also work with other age groups, subjects, and contexts?

An additional point: in the control classes, the approach was primarily constructivist. The comparison was therefore implicitly “constructivist versus explicit,” rather than “everything teachers normally do versus explicit.” This makes the conclusions both more precise (because the differences are significant) and less broadly applicable. Other teaching practices are also conceivable.

Beyond the “math wars”: towards balanced teaching

What strikes me most is that this research reminds us once again of the need for precision in the educational debate. It’s tempting to caricature constructivism as “letting students swim freely” versus “explicit instruction,” as “drilling.” In reality, it’s about the didactic choices teachers make, depending on learning objectives, age, and context. This research convincingly demonstrates that for crucial basic skills—such as lower-level math—clear explanations, guided practice, and ample feedback make all the difference. But that doesn’t mean there’s no room for discussion, collaboration, or open-ended problems in other phases of learning.

In short, this is robust and relevant research, precisely because it took place in real classrooms with students who need it most. It confirms what many other studies have already suggested. Explicit instruction is not a dogma, but a powerful tool. The challenge remains to use this tool in a way that not only produces short-term learning gains but also sustainable arithmetic skills, confidence, and mathematical insight in the long term.

Abstract of the research:

In France, the proportion of low-achieving students in mathematics has increased, and the difference in results between the socially advantaged and disadvantaged students marks a significant achievement gap. The present research evaluates the effectiveness of socio-constructivist teaching compared to explicit teaching, in enabling second graders to learn subtraction and fifth graders to learn the concept area, in students from disadvantaged social backgrounds. Two randomized controlled pre- and post-tests studies were conducted. Multilevel statistical analyzes were carried out ( N  = 454 and  N  = 321). Results showed that all the students progressed between the two assessments. However, those who were taught using explicit instruction performed better than those who were taught with socio-constructivist teaching (Study 1, Cohen’s  f  = 1.32; Study 2 Cohen’s  f  = 1.62). These results suggest that explicit teaching is particularly appropriate to help low achievers from disadvantaged social backgrounds acquire new, complex, and structured mathematical knowledge.