What is it?
Within-class achievement grouping involves organising students within their usual class for specific activities or topics, such as literacy. Students with similar levels of current achievement are grouped together, for example, on specific tables, but all students are taught by their usual teacher and support staff, and they usually all follow the same curriculum.
The aim of this type of grouping is to match tasks, activities and support to students’ current capabilities, so that all students have an appropriate level of challenge.
Although within-class grouping is sometimes described as ‘ability grouping’, we refer here to ‘achievement’ rather than ‘ability’, as schools generally use measures of current performance, rather than measures of ability, to group students.
For evidence on the impact of grouping students by achievement into different classes, see the ‘Setting or streaming’ Toolkit entry. Other types of achievement grouping, such as grouping by achievement across year groups, and teaching high attaining students with older year groups, are not covered in the Toolkit as they are less commonly used.
How effective is it?
The evidence on within-class achievement grouping indicates that it is likely to be beneficial for all learners, providing an average benefit of three months’ additional progress. However, there appears to be less benefit for lower attaining students than others.
Within-class achievement grouping may also have an impact on wider outcomes such as confidence. Some studies from the broader evidence base conclude that grouping students on the basis of achievement may have longer term negative effects on the attitudes and engagement of low attaining students, for example, by discouraging the belief that their achievement can be improved through effort.
How secure is the evidence?
The evidence has accumulated over at least 50 years, and there are a large number of experimental studies. The conclusions on the impact of within-class achievement grouping are relatively consistent across different evidence reviews. However, most of the reviews present relatively basic analysis. They do not explore whether effects vary between different types of study and different types of grouping interventions and the evidence base would benefit from new reviews which considered these issues in more depth. Overall, the evidence is rated as limited.
The majority of the experimental evidence comes from the USA, and there are few rigorous experimental studies from other countries.
There is more evidence from primary schools than secondary schools, as within-class grouping is more commonly used for younger students.
Studies which measure the impact of within-class achievement grouping often compare it with mixed achievement whole-class teaching. This means it is possible that the positive impact observed is partly or wholly due to grouping, rather than to achievement grouping. To know whether this is the case requires more studies which compare within-class achievement grouping with within-class grouping which is not based on achievement.
Because lower attaining students appear to benefit less than others from within-class achievement grouping, it is important to consider the wider evidence on supporting these particular students when developing strategies to improve their achievement. See for example Small group tuition and One to one tuition.
What are the costs?
Within class grouping by achievement has few associated financial costs. Additional expenditure may be required for additional teaching resources for different groups. Overall the costs are estimated as very low.
What should I consider?
How will you decide which subjects or activities are grouped by current level of achievement and which are not?
How will you ensure that all students receive high quality teaching when different groups are doing different tasks or require different teaching strategies?
How will you minimise the risk of allocating students to the wrong group? Have you assessed whether your grouping criteria could disadvantage certain students? For younger children, have you taken their relative age within the year group into account?
How flexible are your grouping arrangements? Students progress at different rates so regular monitoring and assessment is important to minimise misallocation and ensure challenge for all students.
How will you monitor the impact of grouping on students’ engagement and attitudes to learning, particularly for lower attaining students?