Reply to Vinson: teacher quality is more important than teacher quantity

In the area of school reform, class size reduction seems to hold all the aces. It is popular with academics, teachers, students and parents alike. It seems intuitive that to have fewer children in a class is better.

Many people, including the authors of the recent Vinson Report on Public Education in NSW, would have us believe that research confirms this. Thorough examination of the research on class sizes and student achievement, however, reveals that this belief is misplaced.

First, many studies have methodological problems that make their application in a real world context doubtful. For example, in the largest and most frequently cited study - project STAR in Tennessee - teachers involved in the study were arguably motivated to ensure that the findings were in favour of smaller classes. This incentive would not exist if small classes were implemented across the board.

Second, many studies introduced other reforms such as curriculum changes at the same time as class size reduction, making their separate effects impossible to determine.

Third, even setting aside these methodological problems, the large majority of studies have found no significant effects of class size on student achievement. The remainder has shown small benefits, usually only when classes have less than 20 students.

Fourth, class size effects are mediated by the competence and effectiveness of the teacher.

In fact, the single most important influence on student achievement (apart from intelligence) is teacher quality. What teachers do in the classroom has more effect on how much a student learns than class size, family background or gender. Unlike class size, this relationship has been consistently confirmed by research both in Australia and overseas.

It makes sense. A great teacher in front of a large class is better than a mediocre teacher in front of a smaller class. Conventional wisdom on class size does not stand up to the same scrutiny.

The most common argument for smaller classes is that teachers can spend more time on individual instruction. Average kindergarten to Year 2 class size in NSW is just over 25 students. The recent Vinson Report recommends reducing maximum class size to twenty students. This extra cost of $1150 per year per student, amounting to billions of dollars over the next few years, would buy an extra two minutes per day of individual instruction.

Furthermore, class size research has found that teacher's aides, or team teaching, has no effect on student achievement. This again suggests that the ratio of staff to students is less important than the teacher's qualifications.

What constitutes effective pedagogy is another issue, but there seems to be agreement that teacher education in Australian universities is inadequate in imparting both pedagogical and behaviour management skills to teachers. There is too much emphasis on the theoretical over the practical. New teachers have usually spent only a few weeks in teaching practicum, and support for them in the extremely difficult first year in a school is patently inadequate.

Another problem is the lack of ongoing professional development for classroom teachers. The NSW Department of Education undervalues the need for teachers to be aware of new developments in both curriculum and pedagogy, and teachers have too few incentives to seek out professional development opportunities for themselves.

Smaller classes are hugely popular with classroom teachers, and understandably so. It seems obvious that having fewer students makes their jobs easier. The trouble is that this does not necessarily translate into significantly better learning outcomes.

The reality is that governments have a limited amount of money to spend, even on imperative services such as education. Decisions have to be made about how to spend money in the most effective ways.

When it comes to teachers, quality is far more important than quantity. The push for class size reduction serves only to weaken the case for more urgent and supportable investments, such as improved teacher education, better professional development and a salary structure that rewards good teaching well.