5th February 2020
We have updated our estimates of the number of people who stammer, writes Rachel Everard.
*We have subsequently undertaken further polling to test these figures, please read our article How many adults stammer?, dated February 2022*
The commonly used statistic is that 1% of the adult population stammers and 5% of children stammer at some point. We’ve updated both these figures. According to our research, 3% of the adult population believe they stammer and, working with Action for Stammering Children, the evidence indicates that 8% of children stammer at some point, albeit temporarily.
Stammering in children
The original 5% figure for children came from a UK study in 1964 (Andrews & Harris), where over 1,000 children were tracked from the time of birth throughout the next 16 years. Around 4.9% started to stammer at some point and most stopped stammering, either naturally or with the help of speech therapy.
Most recent studies, summarised by Yairi & Ambrose (2013), revealed a higher percentage of children who started to stammer. For example, Reilly et al conducted a robust study in 2009 involving 1,619 children. Parents were asked to contact the researchers as soon as they noticed their child had started to stammer. The child was then assessed by a qualified speech and language therapist to confirm a diagnosis of stammering. This study found that 8.5% of the children started to stammer.
Stammering in adults
The BSA and Action for Stammering Children worked with YouGov on an Omnibus poll in November 2018 and again in December 2019, which included asking people whether they stammered.
We made it very clear what we mean by stammering: “As a reminder, by ‘stammering or stuttering' we mean when someone struggles to get words out, often repeats or prolongs sounds or words, or gets stuck without any sound. Sometimes this includes putting in extra sounds or words. This is different from the problems most people will commonly experience, the occasional hesitation or stumbling around words...”
In the 2018 poll, 1,975 adults responded to this question, and in the 2019 poll, 2,018 responded. On both occasions, 3% answered 'yes' to this question, rather than the expected 1%.
Updating the estimate
Much of the previous research which contributed to the 1% figure was actually carried out on school children rather than adults, and relied on asking teachers how many pupils in their current class stammer, rather than on close observation or self-report. With this background, our updated 3% figure makes sense — without intending to cause offence to teachers, it could be relatively easy for a child who stammers to slip through the net and not be identified as having a stammer. We know from conversations with our members that people often try and hide their stammer, and our 2019 YouGov poll showed that of 58 people who said they had a stammer, 41 tried to hide it. Even a parent might assume that their child no longer stammers yet the child might have a very different opinion, as a recent study by Franken et al (2018) suggests.
Again, we know from our members that it is not uncommon for people who stammered as children, and who to all intents and purposes no longer visibly stammer, to still experience moments of stammering and work hard to avoid it.
Our aim is to provide a rationale for why we’ve updated our figures. We’d love to hear your thoughts. Do also read the research — the Yairi & Ambrose 2013 paper is particularly useful as it provides an overview of the research studies, how they differ from one another and why we should put more store by one research study than another. You can read it on the National Centre for Biotechnology Information's website here.
Things are never straightforward when it comes to stammering, and that’s true of research into the subject.
Read CEO Jane Powell's thoughts on the findings in her article '1% or 3%'?
What do you think? Tell us about your experiences - go to Twitter and use #3percent
Andrews G. & Harris M. (1964). ‘The syndrome of stuttering’. Clinics in Developmental medicine. (No 17).
Franken, M.J.P., Koenraads, S.P.C., Holtmaat, C.E.M. & van der Schroeff, M.P. (2018). ‘Recovery from stuttering in preschool-age children: 9 year outcomes in a clinical population’. Journal of Fluency Disorders, 58: 34-46.
Reilly S., Onslow M., Packman A., Wake M., Bavin E., Prior M., et al. (2009). ‘Predicting stuttering onset by age of 3: A prospective, community cohort study’. Pediatrics. 123:270–277.
Yairi E. & Ambrose N. (2013). ‘Epidemiology of stuttering: 21st century advances’. Journal of Fluency Disorders 38 66–87.