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The Importance of Class Size

published 28 June 2016 updated 28 June 2016
written by:

Class size research has a protracted and controversial history, especially in the USA, England, and Australia. Is there evidence that pupils taught in smaller classes do better in academic and other non-cognitive outcomes than pupils in larger classes?

Many policymakers and political commentators world-wide suggest that funding isn’t the problem in education. They claim that much of the increased expenditure on education in the last 20 to 30 years has been ‘wasted’ on efforts to reduce class sizes, arguing that this extra funding does not lead to better academic results.

Most of this policy advice and commentary relies heavily on misquoting from Visible Learning by Prof John Hattie and work by selected education econometricians who suggest that the majority of studies around the world have shown that class size reductions do not significantly improve student outcomes.

Commentators and politicians alike point to high performing systems such as Shanghai, Hong Kong, South Korea, Taiwan and Singapore, where large class sizes are the norm, as evidence that reducing class sizes is a futile exercise. But research indicates that students from Confucian heritage cultures are socialised in ways that make them amenable to work in large classes, so that management problems are minimal and teachers can focus on meaningful learning using whole-class methods. An educational system forms a working whole, each component interacting with all other components. Isolating any one component (such as class size) and transplanting it into a different system shows a deep misunderstanding of how educational systems work.

Reducing class size to increase student achievement is an approach that has been tried, debated, and analysed for many decades. The premise seems logical: with fewer students to teach, teachers should achieve better academic outcomes for all students. For those who choose private education for their children, it is often cited as a major consideration. However, for policymakers there are three major questions to answer with the adoption of any change or new program: how effective will the change be; how much will it cost; and what are the problems of implementation, including the support or opposition of the stakeholders – in this case principals, teachers and parents – and those who implement it

Policy makers, politicians and media too often discuss data about class sizes and their impact on student learning without an evidence base, relying largely on second-hand research or anecdotes. Too frequently, advocates for particular positions select their evidence, conveniently ignoring research that raises questions about their favoured position.

In a review of over 120 research papers from 1979 to 2013 I found that Hanushek and Hoxby seemed to stand alone in their findings that class size reduction has little or no impact on student academic outcomes – yet they are disproportionately referred to for evidence here in Australia. In a 2011 court case in the USA about school funding the Judge commented on Hanusheck’s evidence submitted to that trial:

Dr. Hanushek’s analysis that there is not much relationship in Colorado between spending and achievement contradicts testimony and documentary evidence from dozens of well-respected educators in the State, defies logics, and is statistically flawed. … The data underlying Dr. Hanushek’s opinions [are] questionable or problematic and I found him to lack credibility.

Many esteemed education researchers have refuted the work of Hanushek and Hoxby. They point out that Hanushek do not examine class size directly, but rather through a proxy measure intended to represent it (student-teacher ratio ). While teacher quality (and the quality of teacher preparation) is at the heart of the effectiveness of almost any reform, conflating STR with class size reduction fails to focus on the mechanisms thought to be at work in smaller classes.

Hanushek has not responded well to such criticisms; rather, he has found reasons to quarrel with their details and to continue publishing reviews, based on methods that others find questionable, claiming that the level of school funding and the things those funds can buy, such as smaller classes, have few discernible effects. Political conservatives have extolled his conclusions, complimented his efforts, and asked him to testify in various forums where class-size issues are debated. And in return, Hanushek has embedded his conclusion about the lack of class-size effects in a broader endorsement of a conservative educational agenda.

The class size debate should be more about weighing up the cost-benefit of class size reductions (CSR), and how best to achieve the desired outcomes of improved academic achievement for all children, regardless of their background.

Many creditable and peer reviewed research projects have concluded that extra gains associated with long-term attendance in small classes (in the early grades) appeared not only for tests of measured achievement, but also for other measures of success in education and that these gains continued to appear when students – including students that are traditionally disadvantaged in education - were returned to standard classes in the upper grades. These research works also revealed that extra gains from small classes in the early grades are larger when class size is reduced to fewer than 20 students. In other words, when planned thoughtfully and funded adequately, long-term exposure to small classes in the early grades generates substantial advantages for students.

Class size reduction and equity

It is evident that for certain groups of children (Indigenous, low SES and culturally, linguistically and economically disenfranchised (CLED) students in the early years, and children with learning and behavioural difficulties), smaller class sizes and increased Teacher Student Ratio are very beneficial. This holds for student learning outcomes, behavioural modification, and teacher satisfaction. As Lamb, Teese and Polesel have shown, with the increasing residualisation of public schools caused by the flight of cultural capital – itself a result of years of federal and state neglect and artificial choice programs promoting private schools – public schools have a larger proportion of problematic learners, disadvantaged and refugee families, and students at risk of school failure, but have larger class sizes than ever before in comparison with most private schools.

If CSR is introduced in the current policy context of high-stakes testing, together with the inadequate funding of public education in many places, we can expect minimal achievement outcomes.

CSR is part of a system of reforms and problems that need to be considered in a coordinated manner, in relation to both the practice and research of schooling. It necessitates implementation that ‘connects the utilisation of the resources for class size reduction with all curricular, administrative, and institutional efforts that shape teaching and learning’ (Graue et al. 2005, 32).

Reducing class sizes or adding extra teachers also requires a new approach to teaching. As Hattie explains, the problem is that teachers in smaller classes are adopting the same teaching methods as in their previously larger classes. Many of the more powerful influences Hattie identifies clearly show that teachers would be even more effective with smaller classes.

Recommendations for policy change

The strongest hypothesis about why small classes work concerns students’ classroom behaviour. Evidence is mounting that students in small classes are more engaged in learning activities, and exhibit less disruptive behaviour.

The following policy recommendations and principles are therefore suggested:

  • Class size is an important determinant of student outcomes, and one that can be directly determined by policy. Any attempts to increase class sizes will harm student outcomes. (Schanzenbach 2014)
  • The evidence suggests that increasing class size will harm not only children’s academic results in the short run, but also their long-term success at school and beyond. Money saved by not decreasing class sizes may result in substantial social and educational costs in the future. (Schanzenbach 2014)
  • The impact of class-size reduction is greater for low-income and minority children;
  • While lower class size has a demonstrable cost, it may prove the more cost-effective policy overall in closing the widening gap between the lowest and highest achievers, even in tight budgetary conditions;
  • Professional development for all staff involved will increase their knowledge of, and preparedness to use, techniques that are particularly suited to small class environments;
  • Targeting of specific classes and specific year levels for CSR.

To ensure that the schools that need small classes the most get the help they need, public education needs a more nuanced funding program. Well-resourced schools (mainly schools in middle-class suburbs) do not necessarily need the smaller class sizes that disadvantaged schools require. Schools should also look at ways to produce the class size effect by lowering class size specifically for certain periods of instruction in numeracy and literacy classes, using a combination of redeployment of existing staff with the addition of special literacy and numeracy teachers. Targeted class size reductions combined with other proven methods of improving achievement would be a more cost-effective means of increasing student achievement.

Writing about the USA, a researcher concludes:

Many of the individuals who are driving education policy in this country … sent their own children to abundantly financed private schools where class sizes were 16 or less, and yet continue to insist that resources, equitable funding, and class size don’t matter — when all the evidence points to the contrary (Haimson, 2009).

Note: This is a summary of a major review published in April 2014 and available free online in the ANZSOG Journal Evidence Base. Complete references are to be found there.

ReferencesGraue, E, Oen, D, Hatch, K, Rao, K and Fadali, E 2005. Perspectives on Class Size Reduction, Annual meeting of the American Educational Research Association, Montreal, Canada, viewed 17 April 2014, _Class_Size_Reduction.pdf>.Haimson, L 2009. Why Class Size Matters, viewed 20 January 2014.Hanushek, EA 1998. The evidence on class size, Earning and Learning: How Schools Matter, 131–168.Hanushek, EA 1999. Some findings from an independent investigation of the Tennessee STAR experiment and from other investigations of class size effects, Educational Evaluation and Policy Analysis, 21(2): 143–163.Hanushek, EA 2003. The failure of input?based schooling policies, The Economic Journal, 113(485): F64–F98.Hanushek, EA, Mayer, SE, and Peterson, P 1999. The evidence on class size, Earning and Learning: How Schools Matter, 131–168.Hanushek, EA, and Rivkin, SG 2006. Teacher quality, Handbook of the Economics of Education, 2, 1051–1078.Hattie, J 2005. The paradox of reducing class size and improving learning outcomes, International Journal of Educational Research, 43: 387–425.Hattie, J 2008. Visible Learning: A Synthesis of Over 800 Meta-analyses Relating to Achievement: Routledge.Hoxby, CM 2000. The effects of class size on student achievement: New evidence from population variation, The Quarterly Journal of Economics, 115(4): 1239–1285.Jensen, B 2010. Investing in Our Teachers, Investing in Our Economy, Melbourne: Grattan Institute.Lamb, S 2007. International Studies in Educational Inequality, Theory and Policy, Springer.Schanzenbach, DW 2014. Does class size matter? In D. Weitman (ed.), Policy Briefs, National Education Policy Center, School of Education, University of Colorado, Boulder.Teese, R, and Polesel, J 2003. Undemocratic Schooling: Equity and Quality in Mass Secondary Education in Australia, Melbourne University Publishing.

The opinions expressed in this blog are those of the author and do not necessarily reflect any official policies or positions of Education International.