The next time someone says class size does not matter, send them this.

In the 1980s, one of the most important education studies ever conducted set out to answer a simple question. Does class size make a real difference to how children learn?

The study was called Project STAR, and it followed more than 11,000 students in Tennessee. This was not a survey. It was not based on opinion. It was a randomized controlled trial, the gold standard of research.

Students were randomly assigned to either small classes of 13 to 17 students or regular classes of 22 to 25 students. Everything else remained the same.

The results were clear.

Students in the smaller classes performed significantly better in reading and mathematics. The difference was strongest in the early years, from Kindergarten through Grade 3. These early gains were especially powerful for children from lower income backgrounds, helping to close learning gaps at a critical stage of development.

What makes this study even more remarkable is what happened next.

The benefits did not disappear over time. Those same students were more likely to graduate from high school. They were more likely to take college entrance exams. They were more likely to attend college. Later economic analysis even linked smaller class sizes in the early years to higher earnings in adulthood.

This was not a short term boost. It was a lifelong advantage.

And Tennessee was not alone.

In Wisconsin, the SAGE program reduced class sizes to approximately 15 students in the early grades. The outcome was the same. Students in smaller classes achieved higher results in reading and mathematics. Different state, different schools, same pattern.

Across decades of research, the strongest academic gains consistently appear when class sizes drop below 18 students in the early years. Not slightly smaller. Significantly smaller.

There is a simple reason for this.

A teacher has a finite amount of time, attention, and energy in a day. Teaching is not just delivering information. It is observing, guiding, correcting, encouraging, and responding to each individual child.

Every classroom is made up of different personalities, different abilities, different learning speeds, and different needs. Some students require reassurance. Some need extra explanation. Others need to be challenged further.

When there are 30 students in a room, that attention must be divided 30 ways. When there are 15, the dynamic changes completely.

More feedback becomes possible. Stronger relationships develop. Misunderstandings are identified sooner. Confidence grows. Learning accelerates.

This is not theory. It is reality, supported by decades of evidence.

You can debate cost. You can debate logistics. But the impact of smaller class sizes on learning, development, and long term outcomes is undeniable.

Fewer students means more attention. More guidance. More opportunity.

Class size matters.

Written by Dr Brad Johnson

At AIS the maximum class size is 12!