Non-verbal autistic adults - prevalence?

In my Master’s dissertation, I found data that suggested that 30% of autistic people are non-verbal, and that the lack of verbal language was not correlate with cognition (ie, there are many people who have standard IQs and do not have learning disabilities who do not speak). However, when I tried to find evidence of non-verbal autistic adults in real life, I really struggled. Are the statistics wrong? Or are they not organised? Or is there something else going on here?

“Approximately 30% of autistic individuals are non-verbal, defined as using few or no words, for reasons that are currently unknown (Tager-Flusberg and Kasari, 2013). Until very recently, it was assumed that non-verbal autistic people did not speak because they were unable to receive or express language. Recent research and anecdotal evidence from non-verbal autistic individuals who have found other means to communicate has discovered that many non-verbal autistic people have cognitive ability similar to their neurotypical peers (Kedar, 2012). Within the context of community care and integration of people with learning disabilities (Department of Health, 2009), it is now increasingly recognised that non-verbal autistic people can and should participate in society, often with the help of assistive technologies (Dawson and Elder, 2013).”

Kedar, I. (2012) Ido in Autismland: climbing out of Autism’s silent prison. [Place of publication unknown]: Sharon Kedar.

Dawson, G., Elder, L. (2013) Seven Ways to Help Your Nonverbal Child Speak, Autism Speaks, 19 March. [Online] Available from:

Tager-Flusberg, H. and Kasari, C. (2013) Minimally Verbal School-Aged Children with Autism Spectrum Disorder: The Neglected End of the Spectrum, Autism Research : Official Journal of the International Society for Autism Research, 6 (6), pp.468-78.

I don’t know how you would go about getting that 30% figure. Where would you begin to draw a representative sample from? Its obviously come from somewhere, but I wonder if it was taken from a very specific population (people in an autistic school, or seeing doctors?)

But I think the substantive point about making sure that everyone is included and participate in society is a really important one.