Reducing class sizes, setting homework during primary school, and introducing school uniforms are among the least effective ways of improving school results, according to a new ‘Which?’ style guide for education published by the Sutton Trust today.

Significant gains in attainment meanwhile come from proven classroom approaches – providing effective feedback on pupil’s performance, encouraging students to think about their own learning strategies, and getting pupils to learn from each other. Implemented correctly, these approaches can increase pupils’ performance by an extra eight or nine months in a school year for a very low cost, according to the guide.

The pupil premium toolkit, developed by academics at Durham University, provides an easily accessible guide for teachers detailing the approaches they should consider when allocating the Government’s Pupil Premium, summarising the evidence gathered from 1000s of studies involving millions of pupils across the world.

The toolkit finds that the benefits of reducing class sizes “are not particularly large or clear, until class size is reduced to under 20 or even below 15”. Hiring more teaching assistants meanwhile is associated with “very small or no effects on attainment”.

The results are at odds with the current views of most teachers. Nearly three-quarters (73 per cent) of teachers identified reducing class sizes as one of their top three priorities when surveyed by the Sutton Trust as to how they intend to spend the Pupil Premium. And nearly half (44 per cent) said that hiring more teaching assistants was one of their top three priorities.

Sir Peter Lampl, chairman of the Sutton Trust, said: “The key to improving the attainment of disadvantaged pupils is not necessarily how much money is spent in schools, but how much is spent on what is proven to work in the classroom. I hope this guide will be a useful tool for teachers to make informed decisions based on the educational evidence available.”

Professor Steve Higgins, Professor of Education at Durham University, and main author of the toolkit, said: “The aim is to help teachers make best bets, based on research evidence, which will help them improve the learning of their pupils.”

The toolkit assesses over 20 different approaches to improving learning in schools, estimating the extra progress over the course of a school year that an ‘average’ student might expect if this strategy was adopted. It identifies the strength of the existing research evidence and makes an estimate of the costs of adopting the approaches. The toolkit also provides guidance on whether the approaches are applicable to primary or secondary school settings, and in which core subjects – English, maths or science.

Among other lessons, the toolkit finds:

On effective feedback – “One study even estimates that the impact of rapid feedback on learning is 124 times more cost effective that reducing class sizes.”

On peer tutoring – “Benefits are apparent for both tutor and tutee, though the approach should be used to supplement or enhance normal teaching, rather than replace it.”

On meta-cognitive approaches – “Studies report substantial gains equivalent to moving a class from 50th place in a league table of 100 schools to about 25th.”

On homework – “It is more valuable at secondary school level and much less effective for children of primary school age.”

On teaching assistants – “Most studies have consistently found very small or no effects on attainment.”

On school uniforms – “No robust evidence that introducing a school uniform will improve academic performance.”

On reducing class sizes – “Overall the benefits are not particularly large or clear, until class size is reduced to under 20 or even below 15.”

On one-to-one tuition – “Pupils might improve by about 4 or 5 months during the programme, but costs are high as the support is intensive.”

On ability grouping – “There may be some benefits for higher attaining pupils, but these are largely outweighed by the negative effects on attitudes for middle and lower performing learners.”

Notes to Editors

The summary document, published on the Sutton Trust website, represents the first stage of the toolkit. The next stages will involve an evaluation of how a number of schools fare in actually implementing the toolkit, and the development of the toolkit into a more interactive online resource for schools and teachers.