SECONDARY SCHOOL
CLASS SIZES ANDSTUDENT PERFORMANCEIN CANADA
Derek J. Allison

2019

fraserinstitute.org

Contents

Executive summary / iii
Introduction / 1
Research and policy context / 2
Data and methodology / 6
Results / 7
Conclusion / 13
References / 16

About the author / 20
Acknowledgments/ 20

Publishing information/ 21

Supporting the Fraser Institute/ 22

Purpose, funding, & independence
About the Fraser Institute/ 23

Editorial Advisory Board

/ 24

/ 22

fraserinstitute.org / ifraserinstitute.org

Executive summary
Small classes are popular with parents and teachers. They are also expensive. Is the cost worthwhile for governments faced with persistent budget
deficits and escalating education costs? Ontario has decided to seek muchneeded savings by phasing in an increase in secondary school class sizes.
Will this negatively impact student achievement as opponents argue? This
study draws on aggregate data from the 2015 Programme for International
Student Assessment (PISA) to show that provinces with larger reported secondary class sizes than Ontario performed better on standardized measuresof student achievement.
Extensive research into the effects of smaller classes has identified
relatively small positive benefits in the lower grades and yielded inconclusive results for the higher grades, with some evidence of higher achievementscores in schools with larger secondary classes. This was the pattern foundin this study.
Canada has traditionally performed well in the PISA results, and did so
again in 2015, placing 10th in math, 7th in science and 3rd in reading amongthe 72 participating countries. Not all provinces performed equally well, withthe largest, wealthiest provinces of Ontario, Quebec, British Columbia, andAlberta outperforming the others. Among these “Big Four” provinces, students in Quebec, British Columbia, and Alberta attained the highest scoresin all three subjects.
PISA measures average class size from school principals’ reports. The
reported Canadian average secondary school class size of 26.4 was slightly
higher than the OECD average of 26.1. There was a large range of class sizes
within Canada extending from a low of 22.6 in Saskatchewan to a high of
30.1 in Quebec. Reported class sizes in Ontario (24.8) and British Columbia(25.4) were statistically indistinguishable from four much smaller provinces.
This study finds a positive correlation (r = 0.758, p = 0.011) between
mean subject scores and reported average class sizes: provinces with higher
PISA scores tended to have larger classes. The study charts mean scores forreading, science and math against average class sizes in the Big Four provinces. Despite having the lowest scores in each of the three subjects, Ontario
also had the smallest classes.
fraserinstitute.org / iii

iv / Secondary school class sizes and student performance in CanadaThis finding does not mean or imply that increasing class sizes in secondary schools will increase student scores on standardized tests. Many otherfactors contribute to student outcomes. Still, classroom modifications that
research has identified as being effective can cost much less than subsidizing smaller classes. And, as demonstrated by this study, higher scores can beachieved with larger classes.

fraserinstitute.org

Introduction
In recent decades, Canadian provinces and US states1 have adopted policies
reducing the numbers of students in public school classrooms. This move has
been enthusiastically welcomed by parents and teachers, aggressively promoted by teacher unions, and broadly supported by politicians. Yet smallerclasses increase costs. Boards must hire—or retain as enrolments decline—
more teachers, incurring substantial and continuing salary, benefit, pension,
administrative, and possibly capital costs which ratchet up provincial grants.
For all these reasons Chingos (2011) argues that class size reduction is themost expensive school reform.
Faced with stubborn budget deficits and continuingly rising education costs (MacLeod and Emes, 2019), reversing this policy may appear as an
attractive option. Ontario started down this road in March 2019, announcing
modest increases in average class sizes for Grades 4–8 and more substantial
increases for secondary schools which would add an average of six students
to each class (Ontario, 2019a). The response from teacher unions was ascombative as it was predictable, the secondary teachers’ union most affectedvowing to resist what it predicted would be a loss of 5,700 teaching positions(Alphonso, 2019). Since then, Ontario (2019b) has scaled back the change toa mere half-a-student increase for the 2019/20 academic year, but appears
committed to phasing in the originally announced increase to an average of
28 students over the following three years.
Will this policy change affect student achievement? This study investigates this key question through an analysis of provincial class size and student performance data from the 2015 Programme for International Student
Assessment (PISA). In addition to showing that students in provinces withlarger average class sizes performed better on the PISA tests, the study provides a more complete account of class sizes in Canadian secondary schools
than has been previously available.
1. The US Federal government initiated the subsequent wave of snowballing class size

policies with its 1999 $1.2 billion class size reduction program which was continued insuccessive years until folded into the No Child Left Behind Act in 2001 (US Departmentof Education, 2004). As of 2010, 36 US states had at least one policy limiting class sizes(Zinth, 2010).
fraserinstitute.org / 1

Research and policy context
Proponents of smaller classes argue that fewer students make classrooms easier to manage, allowing for more individualized attention which will increase
engagement and improve student achievement. The considerable body of pertinent research shows smaller classes can make a difference, but the effects
are smaller and more conditional than often claimed, with many other factors influencing outcomes and complicating analysis.
Tennessee’s highly influential Project STAR provided strong but qualified support for the conventional view. From 1985 to 1989, almost 12,000
K–3 students and over 1,000 teachers were randomly assigned to either
small (13–17 students) or regular classes (22–25 students).2 Those in thesmall classes did better on a range of achievement and behavioural measures, with disadvantaged students tending to benefit more (Finn and Achilles,
1999; Schanzenbach, 2006). Improvements in test scores were nonetheless small, although larger in the lowest grades,3 suggesting smaller classes
may particularly help younger children adapt to classroom norms and routines (Guillemette, 2005).4 Subsequent reanalyses found that while all students benefitted from the small classes, higher achievers benefitted more
(Konstantopoulos, 2008). Observed gains in student achievement have also
been linked to more experienced teachers (Krueger, 1999).
Continuing but reduced positive effects from the STAR project havebeen reported as the students progressed through school: fewer small classstudents were retained in grade and they tended to earn higher marks until
the effect on test scores faded into statistical insignificance around Grade 8(Krueger and Whitmore, 2001). Even so, fewer dropped out of high school,
more took advanced-level and foreign language courses, and more were in
2. The Chetty et al. (2011) analysis of adult outcomes for 9,939 Project STAR students

reported the small classes had 15.1 students on average, the regular classes 22.6 students.
Students attended small classes for an average of 2.27 years.
3. Effect sizes (Cohen’s D) of 0.187 and 0.189 standard deviation units in Kindergarten
and Grade 1, and 0.141 and 0.152 in Grades 2 and 3 (Schanzenbach, 2006: Table 4).
4. This plausible theory implies positive benefits of smaller primary level classes could be
reduced as more younger children participate in pre-school, classroom-like experiences.
2 / fraserinstitute.org

Secondary school class sizes and student performance in Canada / 3

the top quarter of their classes (Biddle and Berliner, 2002). Longer term trace
effects have also been detected, Chetty et al. (2011) reporting improved college attendance, home ownership, and savings, although they were unable
to unambiguously identify effects on earnings. Yet despite the influence ofProject STAR on subsequent research and policy, scholars have pointed toflaws in design and execution that lead Hanushek (2003) to caution against
Project STAR being used to justify class size reduction policies.
More recent studies, including examinations of large-scale class size
reduction initiatives in California (Bohrnstedt and Stecher, 2002) and Florida(Chingos, 2010), support Project STAR’s core results: relatively substantial
reductions in class sizes can provide modest benefits in the primary grades,
especially in entry classes. Still, as highlighted in the California results, thesegains can be offset by boards being forced to hire more inexperienced teachers
and the need to form larger and more split grade classes in higher elementary grades. There is little evidence of positive academic effects from smallerclasses in the middle grades, and even less beyond. Neither Hoxby’s (2000)
rigorous natural experimental treatment of Connecticut data nor Shapson etal.’s (1980) Toronto study found positive effects for smaller classes in Grades
4–8. Uhrain’s (2016) recent review of secondary level studies found results to
be inconclusive, while Hanushek and Woessmann’s (2011) detailed discussionof cross-national econometric analyses of school inputs concluded class size
is not “a major driver of student achievement” at the secondary level (p. 138).
Indeed, they reported some evidence of higher achievement in larger secondary school classes (p. 131), a relationship also evident in high performing
Asian systems in the PISA results (OECD, 2016b: 204).
The systemic difficulty in any attempt to assess the effect of class size is
the presence of many other variables affecting classroom dynamics and student outcomes, all of which inevitably interact. Smaller classes can improvelearning environments, but the research has shown that not all teachers takeadvantage of the opportunities created.5 Class activities will also be influenced
by the availability of learning materials, the presence or absence of disruptive
students, more or less supportive school climates, and so forth.
John Hattie’s (2005) extensive examination of student achievement
research found smaller class sizes to be among the least effective intervention.
Hattie’s analysis of 164 class size reduction studies found an average effectsize of 0.13, essentially mirroring the Project STAR results. He notes the variance across the findings reviewed is small and concludes “the typical effect of
reducing class sizes from 25 to 15 is [effect sizes of ] about 0.10–0.20” (p. 396).
His comparative synthesis of research into other ways of increasing achievement ranked class size 40 out of the 46 different classroom interventions
5. This is particularly clear in the Shapson et al. (1980) Toronto study where very few

changes in classroom practices were observed in the smaller experimental classes.

fraserinstitute.org

4 / Secondary school class sizes and student performance in Canada

considered (table 1). Providing feedback to students and using direct instruction methods each had the highest average effect sizes of 0.81. Other notableinfluences included general quality of teaching, with an effect size of 0.67, and,in the more modest range, homework and teacher questioning with average
effect sizes of 0.35 and 0.17 respectively (table 1).6
As Hattie and others point out, the policy implication is not that smallerclass sizes make no difference but that they make a smaller difference, forfewer students, at much greater cost than most other ways of seeking classroom improvement. Given the research evidence, the greatest benefits can be
expected in the lower, particularly the entry, grades. Governments with themeans can thus find some justification for choosing to finance relatively small
entry classes, especially as research (e.g., Shapson et al., 1980) and opinion
surveys show these are popular with parents and they appear to have valuable socialization effects, particularly for disadvantaged children. Still, few
if any governments are likely to fund classes of 15 or so students, which theresearch suggests is the most desirable size for primary level classes.7 Thereis no convincing research evidence or argument supporting such policies atthe secondary level. To the contrary, the larger size, universal enrolment, andcourse- rather than grade-based curriculum of modern secondary schools
encourages a variety of class sizes to best suit different subject and student
configurations. This is typically accommodated by setting average class sizes
at the board or provincial level, providing flexibility for individual schools toestablish classes appropriate to their circumstances.
The policy question thus becomes whether the applicable averages areappropriate under the prevailing circumstances.8 There is obviously no easily
calculated answer to such an open question: an appropriate policy solution
will aim at ensuring schools have sufficient resources to vary class sizes to best
meet their instructional needs while guarding against dysfunctionally large
classes. Ontario is currently phasing in an increase in its board-wide Grades
9–12 average from 22 to 28 students. This will still be below British Columbia’s
stipulated average of 30 and Quebec’s average of 32 students, but a little above
Alberta’s recommended target of 27 students. Ontario’s planned reduction
will produce significant financial savings. But will it negatively affect student
6. Hattie (2008, 2012) has considerably expanded his comparative analysis of classroom

interventions in his more recent publications; a 2019 webpage reports effect sizes for 252
different interventions. On this list class size ranks 186 out of the 235 interventions withpositive effects (Waack, 2019).
7. Quebec caps Junior Kindergarten at 17 students, Senior Kindergarten at 19 and Grade
1 at 22; Alberta has set a recommended target of 17 students in K–3. Regulations in otherprovinces except Saskatchewan establish or encourage primary classes in the 20–27 range.
8. These may include various adjustments or further limits specified in provincial regulations and/or provincially or locally negotiated collective agreements.
fraserinstitute.org

Secondary school class sizes and student performance in Canada / 5

achievement? As reviewed above, the research record suggests not, but thecomplex interplay of pertinent variables makes prediction impossible. Some
insight can nonetheless be gained by examining relationships between average class sizes and student achievement in other provinces.

fraserinstitute.org

Data and methodology
Since 2000, more than half a million 15-year-old students in some 70 countries have participated in the triannual Programme for International Student
Assessment (PISA) sponsored by the OECD. Students take an internationallyapproved two-hour test on reading, mathematics, science, and other domains
such as problem-solving and financial literacy. Students, professional staff,
and parents are also invited to answer questions on school organization, homequalities, and other aspects.
This study draws on provincial level aggregate data from the 2015 PISA
cycle (OECD, 2016a, 2016b). Approximately 20,000 Canadian students inover 700 schools9 participated, 87 percent of whom were enrolled in Grade10.10 PISA test scores are standardized to a mean of 500 points and standard
deviation of 100 for OECD countries.11 Class size averages are derived fromschool principal responses to a questionnaire item.12

9. Both public and private (independent) schools participated, with 6.8 percent of stu-

dents enrolled in independent schools. But provincial coverage was uneven. Provinceswith the highest proportion of private schools were Quebec (17.1 percent), BC (7.9 percent), Manitoba (5.8 percent), and Alberta (2.2 percent). There were no (0 percent) private
schools included in the Ontario sample (OECD, 2016b: Table B2.II.22).
10. More than 90 percent of students in BC, Manitoba, Ontario, and Newfoundland &Labrador were enrolled in Grade 10, between 85 and 90 percent in AB, SK, PE, and NB,
78 percent in Nova Scotia and 65 percent in Quebec.
11. The actual mean for OECD countries in the 2015 cycle was 493 (O’Grady et al., 2016: 19).
12. The item wording is: "What is the average size of <test language> classes in <national
modal grade for 15‑year‑olds> in your school? 15 students or fewer, 16–20 students, 21–25
students, 26–30 students, 31–35 students, 36–40 students, 41–45 students, 46–50 students or more than 50 students."
6 / fraserinstitute.org

Results
Canada has obtained high PISA scores since the inception of the programin 2000. In the 2015 cycle Canada had the 10th highest score in math, 7thhighest score in science, and 3rd highest score in reading from among the 72
participating countries. In each subject domain the Canadian mean scores
were significantly higher than the OECD means and were only exceeded by
one G7 country in one subject, Japan obtaining a mean score of 538 in mathcompared to Canada’s 528. Only Singapore (535) achieved a higher score than
Canada’s 527 in reading, which was matched by Hong-Kong.
Figure 1 charts provincial scores for the three subject domains, showing the Canadian means for comparison. Students in British Columbia andQuebec13 achieved higher average scores in all three subjects than did Canadianstudents overall. Alberta exceeded the Canadian average in science and reading. Ontario’s mean reading score matched the Canadian average. Students in
the remaining provinces scored below the national mean in all three subjects.
Students in all provinces except Quebec attained lower scores in maththan in reading or science. Quebec students reversed this pattern by achieving their highest scores in math, followed by science and then reading. British
Columbia and Alberta students achieved their highest scores in science, followed by reading, a pattern which matches the Canadian averages. Ontario students obtained their highest scores in reading, followed by science and math.
The four provinces with scores above the Canadian average appearing
at the top of figure 1 are also the largest and wealthiest. Between them theyaccounted for 86.9 percent of total public school enrolment in 2014/15,
Ontario enrolling 39.9 percent of all Canadian students, followed by Quebec(23.6 percent), Alberta (12.5 percent) and British Columbia (11.0 percent) (calculated from MacLeod and Emes, 2019: Table 2). Concentrating on secondary school enrolment, these “Big Four” provinces accounted for 84.9 percent
of Canadian Grade 9–12 enrolment in 2014/15 (calculated from Statistics
Canada, 2019). Grade 12 is not included in the Quebec public school sector,
13. The data released by the OECD warns that “[r]esults for the province of Quebec

should be treated with caution due to a possible non-response bias.” See O’Grady et al.
(2016: 69–70) for details.
fraserinstitute.org / 7

8 / Secondary school class sizes and student performance in Canada

Figure 1: Average 2015 PISA scores by subject and province
QuebecBritish Columbia
Alberta
Ontario
CANADA
Nova Scotia
Prince Edward Island
Reading

New Brunswick

Science

Newfoundland & Labrador

Math

Manitoba
Saskatchewan
450

470

490

510

530

550

Source: OECD, 2016a: Tables B2.I.2, B2.I.4, B2.I.10.
Note: Results for Quebec should be treated with caution due to a possible non-response bias.
See O’Grady et al. (2016: 69-70) for details.

which reduces the number and relative proportion of Quebec secondary level
students. This inverts the relationship between secondary enrolment and
PISA scores for the Big Four provinces, with lowest-scoring Ontario enrolling45.2 percent of Grade 9–12 students, Alberta 13.9 percent, British Columbia
13.1 percent, and Quebec 12.7 percent.
There is also an inverse relationship between 2015 PISA scores and perpupil expenditures. Saskatchewan and Manitoba, the two provinces with thehighest 2014/15 per pupil expenditures of $15,040 and $14,498 as reported by
MacLeod and Emes (2019: Table 3), had the lowest PISA scores. Conversely,
Quebec and British Columbia, the best performing provinces in figure 1, had
the lowest per-pupil expenditures of $11,049 and $11,216 respectively. Alberta($13,197) and Ontario ($13,276), the two other high scoring provinces, eachspent more per pupil than Quebec and British Columbia, and more per pupil
than Prince Edward Island ($12,610), Newfoundland and Labrador ($13,174),
and Nova Scotia ($13,179), each of these last three performing below the
Canadian average.
As shown in the broader PISA results (OECD, 2012) and discussed at
length in a recent Fraser Institute study (Krieg, 2019), the amount of money
relatively wealthy jurisdictions spend on schools does not, by itself, directly
improve student achievement. What matters is how the money is spent, classsize being one policy pertinent variable.
Figure 2 charts provincial class size averages as reported by principalsof the secondary schools participating in PISA 2015. Provinces are ranked
along the horizontal axis by increasing class size, ranging from Saskatchewan
fraserinstitute.org

Secondary school class sizes and student performance in Canada / 9

Figure 2: Ranked average secondary school class size by province

Average reported class size

32
30.12

30
28.50

28
27.14

26

26.05
24.76

24.81

24.94

24.96

25.41

24
Canadian average = 26.38

22.63

22

SK

MB

ON

NB

NL

BC

PE

NS

AB

QC

Provinces ranked by average class size
Source: OECD, 2016b: Table B2.II.44.
Note: Results for Quebec should be treated with caution due to a possible non-response bias.
See O’Grady et al. (2016: 69-70) for details.

on the extreme left with the smallest reported secondary school class sizeof 22.63 to Quebec with the largest class size of 30.12. Provinces are ranked
to separate data points and avoid crowding among similar values. The bars
extending from the plotted values map one standard error above and below
the data point, providing a visual indicator of the margin of error associatedwith sampling and measurement. Overlapping bars indicate a 95 percent
chance that the true population means for the plotted values lie within therange mapped by the error bars, implying a lack of statistical significance.
Error bars that do not overlap do not necessarily imply a statistically significant difference unless they are a substantial distance apart.
Using these visual indicators, Saskatchewan stands out in figure 2 ashaving uniquely small secondary school classes. Ontario’s reported secondary
school class average of 24.81 is the third smallest and below the national average of 26.38. As shown in the chart, Ontario’s average secondary school classsize is statistically indistinguishable from the average class sizes in Manitoba,
New Brunswick, Newfoundland and Labrador, British Columbia, and Prince
Edward Island secondary schools.14 In clear contrast, secondary school principals in Alberta and Quebec reported class sizes substantially and significantly

14. A t-test confirmed no statistically significant difference between the reported second-ary school class sizes for Ontario and British Columbia t(209) = 1.02, p = 0.472.

fraserinstitute.org

10 / Secondary school class sizes and student performance in Canada

larger than the Canadian average.15 Nova Scotia occupies an intermediary position in figure 2, but no statistically significant difference was foundbetween the provincial and Canadian average class sizes.16
By way of comparison, Finland (19.07) and Belgium (19.73) had the lowest reported mean class sizes among OECD countries in the 2015 PISA data;
Mexico (39.08) and Turkey (47.15) had the largest, with Turkey appearing asan outlier in the distribution. Among G7 countries, France (29.26) and Japan(36.1) had the largest average class sizes; the United Kingdom (24.35) and
Italy (23.32) had the smallest. When compared to the provincial data, Quebecclass sizes are larger than the national averages for all G7 countries except
Japan, while mean class sizes in Saskatchewan high schools are smaller thanall G7 national averages.
Despite the relatively higher cost of smaller class sizes, Saskatchewan,
as noted earlier, had the highest per-pupil expenditure in 2014/15; Quebec,
with the smallest average class size, the lowest. Various economies and diseconomies of scale associated with population density and system structure are likely at work here, making superficial comparisons difficult. Perpupil spending in the seven provinces with class sizes clustered around theCanadian average ranged from a low of $11,216 in British Columbia to a highof $14,498 in Manitoba, with Ontario’s $13,276 falling in the middle of therange. Alberta stands out with the second largest class size and the second
lowest per-pupil expenditure of $13,197 (MacLeod and Emes, 2019: Table 3).
Figure 3 plots mean PISA test scores against class sizes. The PISA
scores plotted on the vertical axis are means of the reading, science, and mathscores. The horizontal axis plots provincial class sizes by actual values rather
than the ranks used in figure 2.
All of the Big Four provinces have average subject scores above themean, consistent with figure 1. Two of these provinces, Alberta and Quebec,
also have average class sizes significantly larger than the Canadian mean.
In contrast, Ontario and British Columbia have high achievement scoreswith class sizes below the national average, a pattern matching conventional
expectations. The smaller six provinces all have scores below the mean, withclass sizes ranging from a low of 22.6 in Saskatchewan to a high of 27.1 inNova Scotia.
The dotted trend line in figure 3 is the best fit linear regression modelfor the data. The positive slope shows a direct correlation (r = 0.758, p = 0.011)
15. Statistically significant differences between the national and provincial averages andbetween the Alberta and Quebec class sizes were confirmed by t-tests: Canada (M =26.4, SD = 5.59) v. Alberta (M = 28.5, SD = 5.21) t(804) = 3.174, p = 0.002; v. Quebec (M= 30.12, SD = 3.61) t(817) = 6.278, p<0.001.
16. Nova Scotia (M = 27.14, SD = 5.67) v. Canada (M = 26.4, SD = 5.59) t(778) = 0.974,
p = 0.341.
fraserinstitute.org

Secondary school class sizes and student performance in Canada / 11

Average of reading, sciemce and math scores

Figure 3: Average subject scores by class size
540 Mean average score = 512.6

QC

BC
AB

530
520

R2 = 0.575

ON

510

PE

NS

NB

500

NL
MB

490

SK
Average class size = 26.4

480
22

23

24

25

26

27

28

29

30

31

32

Average class size
Source: Subject means calculated from OECD, 2016a: Tables B2.I.2, B2.I.4, B2.I.10. Class sizes from
OECD, 2016b: Table B2.II.44.
Note: Results for Quebec should be treated with caution due to a possible non-response bias.
See O’Grady et al. (2016: 69-70) for details.

between mean subject scores and class sizes at the provincial level, with larger
average class sizes being associated with higher subject scores. Specifically,
the slope of the regression line in the statistical model predicts an estimatedincrease of 5.73 in the subject score for each additional student in a class, witha standard error of 1.74. Such a positive relationship is contrary to conventional expectations, but has been previously reported for secondary schools
as noted earlier.
Nevertheless, the 0.575 R2 coefficient of determination shows there
is a substantial proportion of the variation in the subject scores that is notaccounted for by variation in average class size. This difference is shown by
the distance between the subject scores predicted by the trend line and theactual scores as plotted. These residual values are notably large for Ontario
and British Columbia, the data points for which are plotted further awayfrom the trend line than for any other province, although Manitoba and Nova
Scotia also have large residual values.17 This reflects the influence of factors
on subject scores other than variation in class size.
Figure 4 focusses on the Big Four provinces of Ontario, Quebec, British
Columbia, and Alberta by plotting student scores for the three tested subject domains against average class sizes ranked along the horizontal axis.
Ontario clearly had both the poorest performance in all three subjects and the
17. The actual residual values are 22.4 for BC, 14.0 for Ontario, -10.3 for Manitoba, and-9.1 for Nova Scotia.

fraserinstitute.org

12 / Secondary school class sizes and student performance in Canada

Figure 4: Provincial subject scores by ranked class sizes
550
Reading

PISA scores

540

Science
Math

530

520

510

500

Ontario (24.8)

British Columbia (25.4)

Alberta (28.5)

Quebec (30.1)

Provinces (average class size) ranked by class size
Source: OECD, 2016a: Tables B2.I.2, B2.I.4, B2.I.10; OECD, 2016b: Table B2.II.44.
Note: Results for Quebec should be treated with caution due to a possible non-response bias.
See O’Grady et al. (2016: 69-70) for details.

smallest reported average class size. Alberta, British Columbia, and Quebec all
attained higher PISA scores than Ontario in each of the tested subjects eventhough they had larger classes. Across the four provinces the reading scores
fall within a range of nine points, with no statistically significant differences.
The science scores are spread across a wider range of 17 points, with a muchcloser spread of four points between the three highest scoring provinces, thedifferences between the Ontario score and those for each of the other threeprovinces being statistically significant beyond the 95 percent probability
level (O’Grady et al., 2016: Table B.3.1). Math scores for Ontario and Alberta
cluster close together with both falling bellow the Canadian average of 516.
Quebec’s math score exceeds second place British Columbia by a substantial
22 points and Alberta and Ontario math scores by 33 and 35 points respectively, with the differences between Quebec and British Columbia and thelower scores for Alberta and Ontario being statistically significant beyond
the 95 percent confidence level (O’Grady et al., 2016: Table B.2.2).

fraserinstitute.org

Conclusion
Despite its apparent simplicity, class size is a complex variable in the calculusof education policy. The research literature shows that smaller classes in thelower, particularly entry grades, can have positive effects, although these areless than usually assumed and most clearly associated with classes smaller
than the target of 20 students often advocated in debate. At the secondary
level research has found no clear relationship between smaller classes andhigher student achievement, with some evidence pointing to higher achievement in larger classes. Such a relationship was the central finding of this study:
as shown in figure 3, student achievement was higher in Canadian provinceswith larger reported average secondary school classes.
This does not mean that increasing secondary school class sizes willautomatically boost student achievement. As shown in figure 3, Prince
Edward Island and Nova Scotia both had larger classes than Ontario andBritish Columbia, but had lower scores. A host of other factors play theirpart in the complex interactions contributing to student achievement, manyof which, as shown by Hattie’s (2005, 2012) research touched on earlier, havebeen shown to have a stronger effect on student achievement than does classsize alone. What can be taken from this study is that class size by itself does
not appear to be a limiting factor on secondary level student achievementin Canada. Given this, Ontario’s plan to phase in a higher average class sizeof 28 in Grade 9–12 is not likely to depress student performance. When thisincrease is fully phased in, Ontario secondary schools will still have smaller
average class sizes than provinces with statistically higher 2015 PISA scores.
Concerns that larger class sizes in Ontario secondary schools will necessarily result in lower student achievement find no support in this analysis of themost pertinent research data currently available.
While there can be no guarantee that student achievement in Ontario
will increase with larger secondary school classes, this is possible. If that were
to come to pass, the improvement would most likely be attributable to either
changes independent of the larger classes or to related changes made possible by the larger classes, rather than to the larger classes alone. Instructionalinnovations are examples of independent changes; greater flexibility in setting individual class sizes to better suit subject and student are an example
fraserinstitute.org / 13

14 / Secondary school class sizes and student performance in Canadaof related effects. By definition, improvements from changes of the first kind
will be independent of changes in class size and could occur in any or all of
the three provinces already outperforming Ontario. Even if Ontario’s scores
were to improve with increased class sizes this would not necessarily reduce
the performance gaps with the other Big Four provinces.
Requiring schools to maintain relatively small class sizes is expensive.
Any consideration of the costs must necessarily balance policy goals. In thiscase, is the goal to control class sizes or improve student achievement? Ifsmaller classes are associated with improved performance the two are easily
conflated. Yet given the findings in the research literature and the results ofthis study, a commitment to maintaining smaller classes in secondary schools
may well impede student achievement. Governments may have what appear
to be good reasons for keeping class sizes low, such as minimizing the possibility of teacher strikes. But when there is an educational cost to doing thisas well as a financial cost, the policy calculus changes.
In this context, the central question raised by this study is not whether
the financial cost of a small class policy can be justified, but whether improved
educational outcomes could be gained by investing the money spent to maintain smaller class averages on other initiatives. The Hattie (2005, 2012) analyses discussed earlier identify many potentially better investments, the mostpowerful of which fall under the general heading of improved teacher quality.
An OECD (2012) discussion of PISA findings draws a similar conclusion, noting that “high-performing countries tend to prioritise investment in teachers
over smaller classes” (p. 3).
Given this, variation in teacher quality may be a contributing factor to
the variation in provincial level student achievement reported in this study.
This requires investigation, but no appropriate comparative measures of
initial and in-service training are readily available. A related, potentially more
powerful and more easily adjusted factor is the relative flexibility of schools
to assign teachers to best serve the educational needs of students. Provincial
regulations and local collective agreements differentially limit the ability ofschool leaders to assign teachers to classes best suited to their strengths.
Ontario appears to have a particularly restrictive web of requirements limiting principal discretion in this respect, which may well be contributing to theprovince’s low scores. As discussed by Alger (2014), the outdated approachto teacher salary schedules and lack of performance-related incentive systems to reward outstanding teachers may also be limiting student achievement. In these respects, Ontario’s (2019b) plan to cushion the impact of larger
classes through a $1.6 billion Teacher Job Protection program intended to“help maintain teaching positions, so that staffing reductions can be managed
through teacher retirements and voluntary leaves” may forfeit potential gains
by postponing savings and retaining less effective teachers.

fraserinstitute.org

Secondary school class sizes and student performance in Canada / 15

Alternative ways of seeking improved student achievement need study
and serious consideration as innovations that could be funded with savings
realized from allowing class sizes to increase. Still, when considering how
best to improve student achievement in public schools, policies that allow
individual schools to form classes, set class sizes, and assign teachers to best
pursue educational goals and serve student needs as informed by local knowledge and professional judgments appear inherently preferable to a relianceon centrally imposed regulation.

fraserinstitute.org

References

Alger, Vicki. E. (2014). Teacher Incentive Pay that Works: A Global Survey ofPrograms Improving Student Achievement. Fraser Institute.
Alphonso, C. (2019, March 21). Ontario Teachers’ Union Says Increased
Class Sizes Could Result in Thousands of Lost Jobs, Vows to Fight the
Changes. Globe and Mail.
Biddle, B. J., and Berliner, D. C. (2002). What Research Says About Small
Classes and Their Effects. Education Policy Reports Project (EPSL-0202101-EPRP), Education Policy Studies Laboratory, Arizona State University.
<https://www.researchgate.net/publication/289066106_What_research_says_
about_small_classes_and_their_effects/citation/download>
Bohrnstedt, G. W., and Stecher, B. M. (eds.) (2002). What We Have
Learned About Class Size Reduction. California Department of Education.
Chetty, R., Friedman, J. N., Hilger, N., Saez, E., Schanzenbach, D. W., andYagan, D. (2011). How Does Your Kindergarten Classroom Affect Your
Earnings? Evidence from Project STAR. Quarterly Journal of Economics
126, 4: 1593–1660. <https://doi.org/10.1093/qje/qjr041>
Chingos, Matthew M. (2010). The Impact of a Universal Class-Size
Reduction Policy: Evidence from Florida’s Statewide Mandate. Harvard
University, Program on Education Policy and Governance Working Paper
10-03. <http://www.hks.harvard.edu/pepg/PDF/Papers/PEPG10-03_Chingos.pdf>
Chingos, Mathew M. (2011). The False Promise of Class-Size Reduction.
Center for American Progress. <https://cdn.americanprogress.org/wp-content/
uploads/issues/2011/04/pdf/class_size.pdf>

16 / fraserinstitute.org

Secondary school class sizes and student performance in Canada / 17

Finn, J. D., and Achilles, C. M. (1990). Answers and Questions About Class
Size: A Statewide Experiment. American Educational Research Journal 27:
557–77. <https://doi.org/10.3102%2F00028312027003557>
Finn, J. D., and Achilles, C. M. (1999). Tennessee’s Class Size Study:
Findings, Implications, Misconceptions. Educational Evaluation and Policy
Analysis 21: 97–109. <https://doi.org/10.3102%2F01623737021002097>
Guillemette, Yvan. (2005). School Class Size: Smaller isn’t Better. C. D.
Howe Institute Commentary: The Education Papers No. 215. <https://www.
cdhowe.org>
Hanushek, Eric. (2003). The Failure of Input-Based Schooling Policies.
Economic Journal 113, 485. <http://hanushek.stanford.edu/sites/default/files/
publications/Hanushek%202003%20EJ%20113(485).pdf>
Hanushek, Eric A., and Woessmann, Ludger. (2011). The Economics ofInternational Differences in Educational Achievement. In Hanushek,
Eric, Stephen Machin, and Ludger Woessmann (eds.), Handbook of the
Economics of Education (Elsevier): 89–200. <https://doi.org/10.1016/B978-0444-53429-3.00002-8>
Hattie, John (2005). The Paradox of Reducing Class Size and Improved
Learning Outcomes. International Journal of Educational Research 43, 6:
387–425. <https://doi.org/10.1016/j.ijer.2006.07.002>
Hattie, John (2008). Visible Learning: A Synthesis of Over 800 MetaAnalyses Relating to Achievement. Routledge.
Hattie, John (2012). Visible Learning for Teachers. Routledge.
Hoxby, Caroline M. (2000). The Effects of Class Size on Student
Achievement: New Evidence from Population Variation. Quarterly Journalof Economics 115, 4: 1239–85. <https://doi.org/10.1162/003355300555060>
Krieg, John M. (2019). International Student Assessments: Performance andSpending. Fraser Institute.
Konstantopoulos, Spyros (2008). Do Small Classes Reduce theAchievement Gap between Low and High Achievers? Evidence from
Project STAR. The Elementary School Journal 108, 4: 275–91. <https://doi.
org/10.1086/528972>

fraserinstitute.org

18 / Secondary school class sizes and student performance in Canada

Krueger, Alan B. (1999). Experimental Estimates of Education Production
Functions. Quarterly Journal of Economics 115, 2: 497–532. <https://doi.
org/10.1162/003355399556052>
Krueger, Alan B., and Whitmore, Diane M. (2001). The Effect of Attendinga Small Class in the Early Grades on College-Test Taking and Middle
School Test Results: Evidence from Project STAR. The Economic Journal
111: 1–28. <https://doi.org/10.1111/1468-0297.00586>
MacLeod, Angela, and Joel Emes (2019). Education Spending in Public
Schools in Canada. Fraser Institute.
O’Grady, K., Deussing, M., Scerbina, T., Fung, K., and Muhe, N. (2016).
Measuring Up: Canadian Results of the OECD PISA Study. Council of
Ministers of Education, Canada. <http://www.cmec.ca/Publications/Lists/
Publications/Attachments/365/PISA2015-CdnReport-EN.pdf>
Organisation for Economic Co-operation and Development [OECD](2012). Does Money Buy Strong Performance in PISA? PISA in Focus 13.
OECD. <https://doi.org/10.1787/5k9fhmfzc4xx-en>
Organisation for Economic Co-operation and Development [OECD](2016a). PISA 2015 Results (Volume I): Excellence and Equity in Education.
OECD. <https://doi.org/10.1787/9789264266490-en>
Organisation for Economic Co-operation and Development [OECD](2016b). PISA 2015 Results (Volume II): Policies and Practices for Successful
Schools. OECD. <https://doi.org/10.1787/9789264267510-en>
Organisation for Economic Co-operation and Development [OECD](2017). PISA 2015 Assessment and Analytical Framework: Science, Reading,Mathematic, Financial Literacy and Collaborative Problem Solving, revised
edition. OECD. <http://dx.doi.org/10.1787/9789264281820-en>
Ontario, Ministry of Education (2019a, March). Education that Worksfor You: Modernizing Classrooms. Press Release. Government of Ontario.
<https://news.ontario.ca/edu/en/2019/03/education-that-works-for-you-2.html>
Ontario, Ministry of Education (2019b, August). Ontario Providing
Stability for Students and Families: No Fundamental Changes to Average
Class Sizes for 2019-20 School Year. News Release. Government of Ontario.
<https://news.ontario.ca/edu/en/2019/08/ontario-providing-stability-for-studentsand-families.html>
fraserinstitute.org

Secondary school class sizes and student performance in Canada / 19

Schanzenbach, Diane W. (2006). What Have Researchers Learned From
Project STAR? Brookings Papers on Education Policy. <http://www.jstor.org/
stable/20067282>
Shapson, Stan M., Edgar N. Wright, Gary Eason, and John Fitzgerald(1980). An Experimental Study of the Effects of Class Size. American
Educational Research Journal 17, 2: 141–52. <https://www.jstor.org/
stable/1162479>
Sims, David (2009). Crowding Peter to Educate Paul: Lessons from a Class
Size Reduction Externality. Economics of Education Review 28: 465–73.
<https://doi.org/10.1016/j.econedurev.2008.06.005>
Statistics Canada (2019). Table 37-10-0007-01, Number of students inregular programs for youth, public elementary and secondary schools, bygrade and sex. Statistics Canada. <https://doi.org/10.25318/3710000701-eng>
US Department of Education (2004). A Descriptive Evaluation of theFederal Class-Size Reduction Program: Final Report. Office of the Deputy
Secretary, Policy and Program Studies Service. <http://www.ed.gov/about/offices/list/ods/ppss/reports.html>
Uhrain, Christopher E. (2016). Effect of Class Size on Student Achievementin Secondary School. Unpublished PhD Dissertation. Walden University.
<https://scholarworks.waldenu.edu/dissertations>
Waack, Sebastian (2019). Hattie Ranking: 252 Influences And Effect Sizes
Related To Student Achievement. <https://visible-learning.org/hattie-rankinginfluences-effect-sizes-learning-achievement/>
Zinth, Kyle (2010, April). CES Highlights: Class Size. Education
Commission of the States. <http://www.ecs.org>

fraserinstitute.org

20 / Secondary school class sizes and student performance in Canada

About the author
Derek J. Allison
Derek J. Allison, B.Ed., M.Ed., Ph.D., is Professor Emeritus at the Universityof Western Ontario and a Fraser Institute Senior Fellow. Derek began his
teaching career in England, before moving to Alberta, where he was a school
principal. After undertaking graduate work at the University of Alberta, he
accepted a position with the faculty of education at the University of Western
Ontario where he taught social and legal foundations of education and skillfully guided hundreds of graduate students through advanced research andstudy. He gained acclaim for his teaching, especially his outstanding lectures,and his skill as a mentor and advisor to graduate students. He has an extensive
record in research and publication with particular interests in the organization and operation of schools, theories of leadership, and the philosophy
of inquiry. He is the recipient of 10 teaching awards and the DistinguishedService Award of the Canadian Association for the Study of Educational
Administration.

Acknowledgments
The author would like to thank two anonymous reviewers for their comments,suggestions, and insights, and to thank Deani Van Pelt for introducing him to
Hattie’s work and for her support and encouragement. Any remaining errors
or oversights are the sole responsibility of the author. As the researcher has
worked independently, the views and conclusions expressed in this paper do
not necessarily reflect those of the Board of Directors of the Fraser Institute,the staff, or supporters.

fraserinstitute.org

Secondary school class sizes and student performance in Canada / 21

Publishing information
Distribution
These publications are available from <http://www.fraserinstitute.org> inPortable Document Format (PDF) and can be read with Adobe Acrobat Pro®
or Adobe Acrobat Reader®, versions 8/9 or later. Adobe Acrobat Reader DC®,the most recent version, is available free of charge from Adobe Systems Inc. at<http://get.adobe.com/reader/>. Readers having trouble viewing or printing our
PDF files using applications from other manufacturers (e.g., Apple’s Preview)should use Adobe Acrobat Reader or Adobe Acrobat Pro.

Ordering publications
To order printed publications from the Fraser Institute, please contact the
publications coordinator:• e-mail: sales@fraserinstitute.org• telephone: 604.688.0221 ext. 580 or, toll free, 1.800.665.3558 ext. 580• fax: 604.688.8539.

Media
For media enquiries, please contact our Communications Department:• 604.714.4582• e-mail: communications@fraserinstitute.org.

Copyright
Copyright © 2019 by the Fraser Institute. All rights reserved. No part of thispublication may be reproduced in any manner whatsoever without written
permission except in the case of brief passages quoted in critical articles andreviews.

ISBN
978-0-88975-571-0

Date of issue
September 2019

Citation
Allison, Derek J. (2019). Secondary School Class Sizes and Student
Performance in Canada. Fraser Institute.
<http://www.fraserinstitute.org>.

fraserinstitute.org

22 / Secondary school class sizes and student performance in Canada

Supporting the Fraser InstituteTo learn how to support the Fraser Institute, please contact• Development Department, Fraser Institute
Fourth Floor, 1770 Burrard Street
Vancouver, British Columbia, V6J 3G7 Canada• telephone, toll-free: 1.800.665.3558 ext. 586• e-mail: development@fraserinstitute.org

Purpose, funding, & independence
The Fraser Institute provides a useful public service. We report objective
information about the economic and social effects of current public policies,
and we offer evidence-based research and education about policy options
that can improve the quality of life.
The Institute is a non-profit organization. Our activities are fundedby charitable donations, unrestricted grants, ticket sales, and sponsorships
from events, the licensing of products for public distribution, and the saleof publications.
All research is subject to rigorous review by external experts, and isconducted and published separately from the Institute’s Board of Directors
and its donors.
The opinions expressed by the authors are those of the individuals
themselves, and do not necessarily reflect those of the Institute, its Boardof Directors, its donors and supporters, or its staff. This publication in noway implies that the Fraser Institute, its trustees, or staff are in favour of, or
oppose the passage of, any bill; or that they support or oppose any particularpolitical party or candidate.
As a healthy part of public discussion among fellow citizens who desire to improve the lives of people through better public policy, the Institutewelcomes evidence-focused scrutiny of the research we publish, including
verification of data sources, replication of analytical methods, and intelligent
debate about the practical effects of policy recommendations.
fraserinstitute.org

Secondary school class sizes and student performance in Canada / 23

About the Fraser Institute
Our mis­sion is to improve the quality of life for Canadians, their families,
and future generations by studying, measuring, and broadly communicating
the effects of government policies, entrepreneurship, and choice on theirwell-being.
Notre mission consiste à améliorer la qualité de vie des Canadiens et desgénérations à venir en étudiant, en mesurant et en diffusant les effets des politiques gouvernementales, de l’entrepreneuriat et des choix sur leur bien-être.

Peer review­—validating the accuracy of our research
The Fraser Institute maintains a rigorous peer review process for its research.
New research, major research projects, and substantively modified research
conducted by the Fraser Institute are reviewed by experts with a recognizedexpertise in the topic area being addressed. Whenever possible, external
review is a blind process. Updates to previously reviewed research or new
editions of previously reviewed research are not reviewed unless the update
includes substantive or material changes in the methodology.
The review process is overseen by the directors of the Institute’s research departments who are responsible for ensuring all research publishedby the Institute passes through the appropriate peer review. If a dispute about
the recommendations of the reviewers should arise during the Institute’s
peer review process, the Institute has an Editorial Advisory Board, a panelof scholars from Canada, the United States, and Europe to whom it can turnfor help in resolving the dispute.

fraserinstitute.org

24 / Secondary school class sizes and student performance in Canada

Editorial Advisory Board
Members
Prof. Terry L. Anderson

Prof. Herbert G. Grubel

Prof. Robert Barro

Prof. James Gwartney

Prof. Jean-Pierre Centi

Prof. Ronald W. Jones

Prof. John Chant

Dr. Jerry Jordan

Prof. Bev Dahlby

Prof. Ross McKitrick

Prof. Erwin Diewert

Prof. Michael Parkin

Prof. Stephen Easton

Prof. Friedrich Schneider

Prof. J.C. Herbert Emery

Prof. Lawrence B. Smith

Prof. Jack L. Granatstein

Dr. Vito Tanzi

Past members
Prof. Armen Alchian*Prof. F.G. Pennance*

Prof. Michael Bliss*

Prof. George Stigler* †Prof. James M. Buchanan* †Sir Alan Walters*

Prof. Friedrich A. Hayek* †Prof. Edwin G. West*

Prof. H.G. Johnson** deceased; † Nobel Laureate

fraserinstitute.org