Evidence for Learning: Teaching Assistant Interventions

Teaching Assistant Interventions

Moderate impact for moderate cost based on moderate evidence
Implementation cost
Evidence strength
Impact (months)

Teaching assistants (TAs, also known as classroom support assistants, education support or teachers’ aides) are adults who support teachers in the classroom. TAs’ duties can vary widely, but they are generally deployed in two ways; to support the teacher in the general classroom environment, or to provide targeted interventions, which are often delivered out-of-class. The role can also include administrative support. 

1. TAs can provide a large positive impact on student outcomes, however, how they are deployed is key.

2. The high average impact hides a large variation between the different approaches to TA deployment. Targeted deployment, where TAs are trained to deliver an intervention to small groups or individuals has a higher impact, whereas deployment of TAs in everyday classroom environments has not been shown to have a positive impact on student outcomes.

3. Access to high quality teaching is the most important lever schools have to improve outcomes for their students. It is particularly important to ensure that when students are receiving support from a TA, this supplements teaching but does not reduce the amount of high-quality interactions they have with their classroom teacher both in and out-of-class.

4. Investing in professional development for TAs to deliver structured interventions can be a cost-effective approach to improving student outcomes due to the large difference in efficacy between different deployments of TAs.

The average impact of the deployment of TAs is about an additional four months’ progress over the course of a year. However, effects tend to vary widely between those studies where TAs are deployed in everyday classroom environments, which typically do not show a positive benefit, and those where TAs deliver targeted interventions to individual students or small groups, which on average show moderate positive benefits. The headline figure of four additional months’ progress lies between these figures.

Research that examines the impact of TAs deployed in everyday classroom environments suggests that students in a class with a TA present do not, on average, outperform those in one where only a teacher is present. This average finding covers a range of effects. In some cases, teachers and TAs work together effectively, leading to increases in achievement. In other cases, students, particularly those who are low achieving or identified as having additional educational needs, can perform worse in classes with TAs.

Where overall negative effects 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, such as by making time for discussion before and after lessons.

Research which focuses on TAs who provide one to one or small group targeted interventions shows a stronger positive benefit of between four and six additional months on average. Often interventions are based on a clearly specified approach which TAs have been trained to deliver.

Teachers also report the benefits in terms of workload and reduced stress from working with TAs.

In England, positive effects have been found in studies where TAs deliver high-quality structured interventions which deliver short sessions, over a finite period, and link learning to classroom teaching, such as:

  • Abracadabra (ABRA)
  • Catch Up Literacy
  • Catch Up Numeracy
  • Nuffield Early Language Intervention (NELI)
  • Switch-on Reading
  • Talk for Literacy

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

No published Australasian research has examined the impact of TAs on academic outcomes. The available research explores their roles, how they are supported, and how their roles are perceived in mainstream and Indigenous settings. The research also suggests that TAs need support and training to increase their skills to work with students and teachers. A common issue associated with TAs is that they work in mainstream classrooms supporting students with additional needs, requiring the execution of complex tasks (e.g., curriculum modification and differentiation), but, while many do, they are not required to have any formal qualifications or training in these tasks.

  • The majority of studies were targeted interventions conducted in primary schools – where the impact is typically a little higher (+5 months) than for secondary age students (+4 months).

  • Most of the evidence relates to reading and other aspects of literacy. Impact is lower for mathematics in primary schools (+ 3 months).

  • The majority of effective approaches involve targeted small group or one to one interventions. Impact in small groups tends to be a little lower (+3 months), but this needs to be offset against the greater number of students who benefit.

  • Short sessions of around 30 minutes or so, several times a week are most effective.

  • Approaches involving digital technology can also be effective with TA support.

Schools should carefully consider how TAs are used to support learners from disadvantaged backgrounds. There is evidence that when a TA is used to support specific students routinely in the classroom, the teacher may interact less with these students, meaning that those who need additional teacher monitoring and support may not receive it. Therefore, additional care should be given to how teachers respond to the deployment of TAs and who they are supporting, particularly for previously low achieving or disadvantaged students.

However, well-evidenced TA interventions can be targeted at students that require additional support and can help previously low achieving students overcome barriers to learning and catch-up’ with previously higher achieving students.

Schools should carefully monitor TA interventions to ensure they are well-delivered, so that students receive the large benefits of structured interventions and not the limited impact of general deployment.

TA interventions have an impact through providing additional support for students that is targeted to their needs. In order to have the desired effect schools might consider:

  • Careful assessment of students’ needs so that TA support is well targeted.
  • Training TAs so that interactions are high quality – for example, using well-evidenced targeted programs.
  • Ensuring that any interventions are well-linked to classroom content and do not reduce high quality interactions with teachers.

High quality communication between TAs and classroom teachers is likely to support good implementation of TA interventions. Studies were not included where the TA was assigned as support for an individual student with a disability. 

TA interventions are typically delivered over half-term or term-long periods when adopting a targeted intervention or approach, or across the entire academic year when deployed more generally.

When introducing new approaches, schools should consider implementation. For more information see Putting Evidence to Work – A School’s Guide to Implementation.

Overall, the median costs of implementing TA interventions are estimated as moderate. The costs associated with the effective deployment of TAs arise from staff salary expenses, the majority of which are recurring costs.

Whilst the median cost estimate for the effective deployment of TA interventions is moderate, differences in training and resource costs through specific TA taught programs or interventions means that costs can range from very low to high. Evidence suggests that the more effective approaches are structured and involve high-quality support and training, so it is important that TAs have professional development in the pedagogy and content of the specific intervention they are expected to use.

These cost estimates assume that schools are already paying for teacher time to work with and support teaching assistants, and the facilities and materials required to implement a TA intervention. These are all prerequisite costs of using TA interventions, without which the cost is likely to be higher.

The security of the evidence around TA interventions is rated as moderate. 65 studies were identified.

Overall, the topic lost an additional padlock because a large percentage of the studies were not independently evaluated. Evaluations conducted by organisations connected with the approach – for example, commercial providers, typically have larger impacts, which may influence the overall impact.

Evidence strength
Number of studies65
Review last updatedJune 2021