Pupils with similar levels of current attainment are grouped together either for specific lessons on a regular basis (setting or regrouping), or as a whole class (streaming or tracking). The assumption is that it will be possible to teach more effectively or more efficiently with a narrower range of attainment in a class.
Overall, setting or streaming appears to benefit higher attaining pupils and be detrimental to the learning of mid-range and lower attaining learners. On average, it does not appear to be an effective strategy for raising the attainment of disadvantaged pupils, who are more likely to be assigned to lower groups.
Low attaining learners who are set or streamed fall behind by 1 or 2 months per year, on average, when compared with the progress of similar students in classes with mixed ability groups. It appears likely that routine setting or streaming arrangements undermine low attainers’ confidence and discourage the belief that attainment can be improved through effort. Research also suggests that ability grouping can have a longer term negative effect on the attitudes and engagement of low attaining pupils.
In contrast, studies show that higher attaining learners make between 1 and 2 additional months' progress when set or streamed compared to when taught in mixed ability groups. This is unsurprising: studies of targeted interventions for pupils identified as "gifted and talented" show that they benefit from a range of different kinds of grouping, including pull-out classes, accelerated classes and promotion (where high attaining pupils move up a year). However, research into gifted and talented schemes rarely records the impact of the schemes on the students not identified as gifted and talented, who are more likely to be from disadvantaged backgrounds. It is possible that, as with setting and streaming, those not identified as gifted and talented experience a negative impact.
Though the average impact of setting or streaming on low attaining pupils is negative, evidence suggests that certain types of grouping are more effective than others. Some studies have shown that reducing the size of the lowest attaining groups and assigning high-performing teachers to these groups can be effective, as can providing additional targeted catch up support (see Small group tuition).
The evidence on setting and streaming is fairly consistent and has accumulated over at least 30 years of research. The majority of the evidence comes from the USA, and there are few rigorous UK studies. Although there is some variation depending on methods and research design, conclusions on the impact of ability grouping are relatively consistent.
Setting and streaming are organisational strategies that have few associated financial costs. Additional resources may be needed if setting or streaming resulted in greater numbers of classes. Overall the costs are estimated as very low.
For low attaining pupils, flexible within-class grouping is preferable to tracking or streaming.
It is important to recognise that a measure of current attainment, such as a test, is not the same as a measure of potential.
How will you ensure that your setting or streaming approach enables more effective teaching for all pupils, including lower attaining pupils?
How will you monitor the impact of ability grouping on pupil engagement and attitudes to learning?