At the Primary level yes probably and small classes help disadvantaged pupils

But evidence less clear post Primary


Well, yes, small class sizes, according to a recent study by a Harvard Professor, do help, certainly in primary  education.

Wishing to obtain data on the effectiveness of reduced class size before committing additional funds,  as the Guardian recently highlighted,the Tennessee legislature in the USA authorized a four-year study in which results obtained in kindergarten, first, second, and third grade classrooms of 13 to 17 pupils were compared with those obtained in classrooms of 22 to 25 pupils and in classrooms of this larger size where the teacher was assisted by a paid aide. Both standardized and curriculum-based tests were used to assess and compare the performance of some 6,500 pupils in about 330 classrooms at approximately 80 schools in the areas of reading, mathematics, and basic study skills. After four years, it was clear that smaller classes did produce substantial improvement in early learning and cognitive studies and that the effect of small class size on the achievement of minority children was initially about double that observed for majority children, but in later years, it was about the same.  The second phase of the project, called the Lasting Benefits Study, was begun in 1989 to determine whether these perceived benefits persisted. Observations made as a part of this phase confirmed that the children who were originally enrolled in smaller classes continued to perform better than their grade-mates (whose school experience had begun in larger classes) when they were returned to regular-sized classes in later grades. Under the third phase, Project Challenge, the 17 economically poorest school districts were given small classes in kindergarten, first, second, and third grades. These districts improved their end-of-year standing in rank among the 139 districts from well below average to above average in reading and mathematics.  Other evidence comes from a longitudinal British study that tracked more than 10,000 pupils in 300 schools from entry to the end of primary. Care was taken to measure factors other than class size that could influence outcomes. Small classes (under 25) had a significant effect on literacy and maths in the first year. This effect endured for literacy (but not maths) in the second year. However, the literacy effect disappeared by the third year, as many of the pupils moved into larger classes. Why though does the size of class make a difference? Teachers spend more time with pupils, individually; the classes were easier to control; and more time could be spent in planning and marking work. Consequently, pupils are better behaved and are more engaged in the process of learning. They asked more questions, discussed subjects with teachers, and were more inquisitive. While bad teachers are not made good by small classes, and while there is a danger that teachers with small classes sometimes fail to adapt their techniques to individualise the pedagogy (having been trained to deal with large ones), particularly for the early years, small is definitely best.  Significantly there is little evidence that teaching assistants improve educational outcomes. While they clearly free up the teacher to provide more individualised attention, they do not have the same effect as simply having smaller classes: results in maths and literacy are not improved by having teaching assistants. So if you want to improve performance don’t expect Teaching Assistants to make much difference.


A recent guidance report to help Free schools, from CFBT Education Trust, Myths, evidence and innovation: a guide to   making the most of Free School freedoms –B. Lipson’ found,  having sifted the evidence ,‘  that reducing class size seems to have greater impact in the earliest grades and for students from  less advantaged family backgrounds.’  So pretty much in line with the Tennessee study. But the report  also cited evidence from Professor Hanushek  who stated: ‘the broad array of approaches, with different  methodologies and sources of evidence, has provided quite a consistent message that broad  reductions in class size are unlikely to produce significant improvements in student achievement.’ In short, Hanuskek says that small class size policies are expensive and largely ineffective.  But while most agree that reducing class sizes   is expensive, the balance of evidence does seem to suggest that small class sizes have an impact at the Primary level, but  that this is less evident at the Secondary level. Educators and politicians have to make a judgement as to whether the expense is justified or whether there are more cost effective ways of raising performance.   But, as ever, it’s the quality of classroom teaching that has the most significant impact on pupil  performance.

The Tennessee Study of Class Size in the Early School Grades; Frederick Mostelle. Professor emeritus of mathematical statistics departments of Statistics and of Health Policy and Management at Harvard University.

Professor Peter Blatchford, visit