By Derek J. Allison
Class size is a hot topic once again in British Columbia.
Back in 2016, the BC Teachers’ Federation won a famous and unique victory when the Supreme Court reinstated class-size limits that had been unilaterally stripped from teacher contracts by the BC Liberal government. Those limits are now at the centre of contract negotiations between the BCTF and the NDP government.
The union, of course, wants to protect smaller classes and can expect support from parents. In a recent Research Co. survey, 21 per cent of B.C. parents said large classes are the biggest problem facing the education system. But smaller classes are expensive. More teachers must be hired at a time of continuing teacher shortage.
So what are the arguments for smaller classes? Conventional wisdom holds that fewer students allow teachers to better individualize instruction and spend more time helping kids learn. There’s research support for this, but it turns out that smaller classes make less of a difference, for fewer students, under more restricted circumstances than generally thought. The greatest and most consistent benefits occur in the primary, especially the early grades. Effects fade in the middle grades. And there is no consistent evidence of improved student performance in smaller high school classes.
To the contrary, a recent Fraser Institute study found that students in Canadian provinces with larger high school classes performed better on standardized tests.
The study used aggregated data from the Programme for International Student Assessment (PISA), which measures the performance of 15 year olds from more than 70 countries every three years. Reports from school principals are used to measure average class sizes.
Canada has an excellent PISA record, placing 10th in math, 7th in science and 3rd in reading among the 72 countries participating in the most recent 2015 cycle. Yet Singapore, the top-scoring country in math and science, had eight more students (on average) in its high school classes than Canada. Japan, the top-scoring OECD county in math and science, had nine more students in its high school classes.
Across Canada, there’s considerable variation among provinces, ranging from a low of 22.6 students per class in Saskatchewan to a high of 30.1 in Quebec. B.C. falls in the middle (25.4 students), slightly below the Canadian average (26.4).
Saskatchewan, with the smallest average high school class size, had the lowest test scores in all three PISA subjects—reading, math and science.
Quebec, which had the largest average class size, had the highest math scores. Alberta, with the second-largest class size (28.5 students), had the highest science scores while B.C. had the highest reading scores. Ontario had the smallest class size—and lowest test scores in all three PISA subjects—among the four largest provinces.
Of course, these findings do not show that larger high school classes will produce better test results. Far from it. There are many variables involved in the dynamics of classroom instruction and school effectiveness.
But the high cost of subsidizing smaller class sizes should be balanced against the better returns that could be gained from investing in more promising initiatives such as improving teacher quality and teaching practices. Might B.C. teachers be willing to trade the cost of small classes for higher salaries? This could be a powerful move, especially if linked to an effective and fair system of identifying, rewarding and retaining excellent teachers.
Derek J. Allison is a professor emeritus of education at the University of Western Ontario, Fraser Institute senior fellow and author of Secondary school class sizes and student performance in Canada.