What Works database

A database of evidenced interventions to support children’s speech, language and communication skills.

What Works database

The Communication Trust worked with the Better Communication Research Programme to develop the What Works database of evidenced interventions to support children’s speech, language and communication. What Works is endorsed by the Royal College of Speech and Language Therapists.


What Works is a moderated online library of evidenced interventions that aim to support children’s speech and language.

What Works is a database that aids early years practitioners, teachers, school leaders, and speech and language therapists in identifying the most suitable interventions for children and young people. It offers a free and easily accessible overview of the evidence base for each intervention. While not designed for commissioners, What Works may serve as a valuable reference during the commissioning process.

Users can search for interventions by target group, age range, focus of the intervention, who it’s delivered by and in what type of format. The evidence for each intervention is rated as ‘strong’, ‘moderate’ or ‘indicative’ as determined by an academic Moderating Group, with a summary of the evidence base and academic references provided.

What Works is maintained and further developed by the Moderating Group, representatives from the Royal College of Speech and Language Therapists and The Communication Trust. This group meets quarterly to ensure that What Works remains as up-to-date and as comprehensive as possible through a robust and independent process to ensure quality and fairness of approach.

What Works has been developed from a report by the Better Communication Research Programme (BCRP). Please click here to read the full report entitled, ‘What Works: Interventions for children and young people with speech, language and communication needs.’

Some key considerations when using What Works

What Works aims to support decision making, not determine it.

  • The Communication Trust does not endorse interventions that have been included on What Works but seeks to make the academic evidence base on each as accessible as possible so that practitioners can make informed choices.
  • Any practitioner views presented on the site in reference to specific interventions, e.g. within case studies, are solely their own and not those of The Communication Trust or the What Works Moderating Group.
  • Evidence about what has worked in the past offers no guarantee that an approach will work in all circumstances; users are encouraged to look at the detail of each intervention to ensure they understand all details and for which children it is most beneficial
  • Although every effort has been made to ensure the accuracy of the information given, no legal responsibility is accepted for any errors, omissions or misleading statements.
  • What Works includes reference to a range of research and publications of third parties; The Communication Trust is reporting on information available in the public domain, but is not responsible for, and cannot guarantee the accuracy of the original publications or related material. Users are encouraged, as they would with all research, to read with a critical eye.

What Works is designed primarily for practitioners – teachers, school leaders, early years practitioners, and speech and language therapists – to help you find the best interventions for those children and young people you work with that have speech, language and communication needs (SLCN).

What Works offers essential information about various speech and language interventions. This seeks to help practitioners in making informed decisions about the interventions that will work best for them and the children and young people they work with.

Considering the range of evidence-based interventions available is essential when seeking the best way to support each child or young person, and What Works aims to make all this information available to practitioners in a free and easily accessible format.

What Works can help build a greater understanding of the available evidence base for speech and language interventions, and also aims to support practitioners and others to become a part of the process of developing the evidence. We welcome practitioners to get involved with this in a number of ways – you can:

  • Submit an intervention to What Works
  • Share your experiences of using interventions on What Works and how they have worked in practice
  • Share your feedback to help us improve What Works – please email info@speechandlanguage.org.uk

To find out what others using What Works have to say about it, please click here to read a summary of our most recent survey.

What Works allows users to search for interventions by target group, age range, focus of the intervention, who it’s delivered by and in what type of format.

There are three ways to view interventions:

  • Filter results by any or all of the above criteria
  • Search by the first letter of the intervention’s name
  • Browse all the interventions by clicking on “Search all interventions.”

Each listing provides information about the aims of the intervention, how it should be delivered and what evidence there is for the intervention. The evidence for each intervention is rated as ‘strong’, ‘moderate’ or ‘indicative’ as determined by a Moderating Group of academics. Please keep in mind that this classification refers to the design and strength of the research, not the outcomes for children.

Anyone can submit an intervention for review by the What Works Moderating Group at one of their quarterly meetings; in order to keep What Works as up-to-date and comprehensive as possible submissions and recommendations are very much encouraged.

The What Works Moderating Group

There is a robust and independent process in place to ensure quality and fairness of approach when making decisions on which interventions are included on What Works. A Moderating Group of academics review each new submission to the database and make a decision as to whether it should be included on the site. They will also categorise its current level of evidence as either ‘indicative,’ ‘moderate,’ or ‘strong.’ The members of the Moderating Group are:

If you would like a new intervention to be considered for inclusion, complete both the criteria for inclusion form and the submission form. Return both of these along with supporting materials to info@speechandlanguage.org.uk.

Practitioners play an essential role in helping to keep What Works a relevant and useful tool. We have received helpful feedback from users which has prompted some important changes to the site, so please do let us know about your experience of using What Works and anything you think we can do to improve it via e-mail at info@speechandlanguage.org.uk.

Your experiences 

We want to hear from practitioners who have used interventions on What Works. How have they worked in practice? How is your team using What Works to support evidence informed practice locally? Your experience of an intervention can provide useful information for other practitioners and help create a much fuller picture of how things work in practice. If you’d like to share your experience, we would love to hear from you.

Suggesting new interventions

If you have a recommendation for a new intervention for What Works, please email us at info@speechandlanguage.org.uk.

Join the What Works Moderating Group

The Moderating Group plays a critical role in steering the development of What Works and setting criteria for inclusion.

The evidence around interventions for children and service delivery can be complex. What Works aims to be clear and transparent about what constitutes good evidence and to provide the necessary information about interventions that will make the site a useful tool to support decision making.

Although randomised control trials and systematic reviews are usually considered the gold standard of research, to avoid excluding interventions which may achieve good outcomes but which have not yet been evaluated in this way, we have not limited the evidence base to these levels.

Instead, we have included a range of evidence levels representing a good level of evaluation. A set of criteria is applied to every intervention, ensuring robust and transparent decisions are made on which interventions to include and at which level of evidence.

For more information on the evidence levels and the criteria, please see our guide, which explains each of the criteria in detail.

Strength of evidence versus strength of outcomes​

It’s essential whilst using the database to be aware of the important distinction between the strength of the evidence and the strength of the intervention’s outcomes for children and young people. This is due to some interventions on the database not having wholly positive outcomes for children but still being included on the database because of the strength of research.  Strong evidence doesn’t necessarily mean an intervention works well. Equally other interventions may only be classed as “indicative” in terms of research design, but the outcomes for children look very good indeed.

It is therefore important when making decisions around which interventions to use not to choose interventions based solely on levels of evidence, as an intervention at a lower level of evidence may be more appropriate and may show better outcomes.

Looking at the effect sizes of interventions on specific outcomes can support practitioners to interpret whether an intervention is appropriate for their setting. Effect sizes of interventions can  be viewed on theWhat Worksdatabase via a graphic which is linked to from each intervention’s page. Each graphic provides information on the outcome that the intervention had the largest effect on, the smallest effect on and the effect size for the primary outcome as stated by the researchers (in other words what the researchers were primarily looking at in their study).

Effect sizes were drawn from the study which provided sufficient evidence to calculate them given the means and standard deviations, these may not be representative of all the studies for this type of intervention.

For more information on this, see our animation and guidance here.

Why do interventions not make it on to What Works?

Interventions are not included if they have limited or weak evaluations; or evaluation information is not readily available in the public domain.

In March 2014 The Children and Families Act received Royal Assent. It includes clauses on special education needs (SEN) which aim to reform the SEN system. These changes, known as the SEN and Disability Reforms, came into effect in September 2014, with a new SEND Code of Practice, the statutory guidance relating to the Children and Families Act.

The 2014 SEND Code of Practice applies to all organisations who work with and support children and young people with special educational needs and disabilities, including local authorities, health agencies, early years providers and all schools.

The Code emphasises the importance of ‘high quality provision to meet the needs of children and young people with SEND’, noting that this includes the use of evidence-based interventions and approaches. Educational settings, joint-commissioning arrangements and local authorities are therefore responsible for accessing the best evidence available on interventions and approaches to support children and young people.

More detail on what the Code of Practice says about evidence-based practice and how What Works supports this is available in our factsheet on What Works and the SEND Reforms.

Other resources on the SEND Reforms and speech and language challenges

The Communication Trust is committed to supporting all those implementing the SEND Reforms to meet the needs of children and young people with speech and language challenges and their families.  In order to achieve this, we are working with the Department for Education, the Pathfinder programme, partners across the VCS sector, and professionals that make up the children’s workforce. You can find out more about our work here.

"Completely relevant: it collects in one place information and evidence about all approaches I use. Finally!"