A class larger than X is qualitatively different from a smaller class. This is intuitively obvious to experienced teachers, but not well supported in Effectiveness research. Darius Lakdawalla wrote in 2002 that there is little or no evidence of benefit from smaller class sizes and pointed out an economic effect:

The rising price of skill means that it is cheaper for schools to improve education by lowering class sizes than by attracting more skilled teachers. Schools will thus compensate for the loss of skilled teachers by reducing class sizes. This helps to understand the long-standing and continuing push for smaller classes in the United States.

Nevertheless, responding to NSW teachers’ claims and American findings that maximum learning occurs in small classes, the NSW government undertook to limit kindergarten classes to 20 students.

There is fresh reason to think that this might be appropriate. C. Northcote Parkinson noted that discussions in a group of mature, engaged, externally motivated adults is distinctly less efficient in committees larger than 20. Recently-published investigation by Thurner, Klinek and Hanel has now found strong correlations between effectiveness and size of national Cabinets that supports this.

Now, children are not adults and the task of a class is not the same as the task of a committee. But we should at least expect peer-learning to be qualitatively different in large classes.

Is educational effectiveness of small classes hard to demonstrate because we are failing to measure important educational outcomes? Or is the learning of children insensitive to the dynamics found in adult committees? Or are teachers completely failing to respond to the difference between large and small class dynamics?

References

1. Photograph courtesy of Hoover Institute, retrieved 10/05/2008 from http://media.hoover.org/images/ednext20023_66d.jpg
2. Graph courtesy of PhysicsWorld.com, retrieved 10/05/2008 from http://images.iop.org/objects/physicsweb/news/thumb/12/4/22/cabinet1.jpg
3. Leete, J., 2002, Class sizes focus on the early years. Retrieved 10/05/2008 from http://www.nswtf.org.au/edu_online/29/class.html
4. National Education Association 2008, Class size. Retrieved 10/05/2008 from http://www.nea.org/classsize/index.html
5. NSW Department of Education and Training 2007, Class size reduction program. Retrieved 10/05/2008 from http://www.schools.nsw.edu.au/studentsupport/programs/classsize/index.php
6. Johnston, H. 2008, Physicists quantify the coefficient of inefficiency. PhysicsWorld.com 27 Apr 2008. Retrieved 10/05/2008 from http://physicsworld.com/cws/article/news/33926
7. Lakdawalla, D. 2002. Quantity over Quality. Hoover Institute. Retrieved 10/05/2008 from http://www.hoover.org/publications/ednext/3365326.html