There is substantial research and debate about class size. Much of the argument focuses on what an appropriate number of students should be in any given classroom. While an argument can be made for including all types of classes, the discussion here is limited to academic classes. A subset of the class-size argument centers on the grade level, namely elementary versus high school. A second subset of the argument presents the long-term gains from smaller class size.

The conclusions of the research:

• The literature is split on the benefits of smaller class size.
• There is support for smaller class size benefits for elementary grades.
• Smaller class sizes are most beneficial when used in grades K-3. The academic discipline instilled at this level generally carries forward to higher grades.
• Benefits of class-size reduction are lost beyond fifth grade.
• Smaller class sizes require more teaching staff and related classroom material.
• Smaller class sizes require additional classrooms and should be considered in light of available quality academic space.
• Smaller class size requires investment in teacher training to generate gains from the smaller class sizes.
• Reductions in class size to less than 25 students are the most beneficial.
• Academic arguments have been made to reduce class size below 15, however the research does not support significant academic gains for class sizes below 25.

Summary
Class-size reductions can improve student outcomes. But the benefits are short lived and are mitigated by age. If a district is going to implement class-size reduction, then it is most effective to reduce class sizes in grades K-3. Reduction of class sizes must be accompanied by an increase in the number of teaching staff and will require appropriate classroom space to accommodate the additional classes.