Teaching assistants

Teaching assistants (also known as TAs or classroom support assistants) are adults who support teachers in the classroom. Teaching assistants’ duties can vary widely from school to school, ranging from providing administrative and classroom support to providing targeted academic support to individual pupils or small groups.

How effective is it?

Evidence suggests that TAs can have a positive impact on academic achievement. However, effects tend to vary widely between those studies where TAs provide general administrative or classroom support, which on average do not show a positive benefit, and those where TAs support individual pupils or small groups, which on average show moderate positive benefits. The headline figure of one additional month’s progress lies between these figures.

Research that examines the impact of TAs providing general classroom support suggests that students in a class with a teaching assistant present do not, on average, outperform those in one where only a teacher is present. This average finding covers a range of impacts. In some cases teachers and TAs work together effectively, leading to increases in attainment. In other cases pupils, particularly those who are low attaining or identified as having special educational needs, can perform worse in classes with teaching assistants.

Where overall negative impacts have been recorded, it is likely that support from TAs has substituted rather than supplemented teaching from teachers. In the most positive examples, it is likely that support and training will have been provided for both teachers and TAs so that they understand how to work together effectively, e.g. by making time for discussion before and after lessons.

There is also evidence that working with TAs can lead to improvements in pupils’ attitudes, and also to positive effects in terms of teacher morale and reduced stress.

Research which focuses on teaching assistants who provide one to one or small group support shows a stronger positive benefit of between three and five additional months on average. Often support is based on a clearly specified approach which teaching assistants have been trained to deliver. Though comparisons with qualified teachers suggest that teaching assistants tend not to be as effective in terms of raising attainment (achieving, on average about half the gains), studies suggest that benefits are possible across subjects and at both primary and secondary level.

How secure is the evidence?

Overall, the level of evidence related to teaching assistants is limited. A number of systematic reviews of the impact of support staff in schools have been conducted in the UK and internationally. However, there are no meta-analyses specifically looking at the impact of teaching assistants on learning.

Correlational studies looking at the impact of TAs providing general classroom support have shown broadly similar effects. One of the most recent studies, conducted in England, suggests that on average low attaining pupils do less well in a class with a TA present, compared to a class where only a teacher is present. More recent intervention studies, including two randomised controlled trials conducted in England in 2013, provide a strong indication that TAs can improve learning if they are trained and deployed carefully. Given the limited amount of existing evidence, these studies made a substantial contribution to the overall evidence base, changing the overall average impact from zero to one additional months' progress.

The research literature does not distinguish between different levels or grades of teaching assistants.

For full references and effect sizes, please click here.

What are the costs?

The average cost of employing a teaching assistant, including salary and on-costs, is estimated at about £18,000. Overall, costs are estimated as high.

What should I consider?


  1. Have you identified the activities where TAs can support learning, rather than simply managing tasks?

  2. Have you provided support and training for teachers and TAs so that they understand how to work together effectively?

  3. How will you ensure that teachers do not reduce their support or input to the pupils supported by TAs?

  4. Have you considered how you will evaluate the impact of how you deploy your TAs?