Picture Exchange Communication System and Autism Ranking:

Status Research

There are a number of limitations to all of the research studies published to date. For example

• The overwhelming majority of studies consisted of single-case designs with small numbers of participants (mostly three, four or five participants).
• Some of these single-case design studies used extremely weak methodologies (such as descriptive case studies).
• There were five group studies but only three of these were randomised and none of them was fully blinded.  One of these studies (Lerna et al, 2012) only had 18 participants. 
• Some of the studies did not provide enough details about the participants, such as whether they had a formal diagnosis of autism, their level of intellectual ability, their ethnicity etc.
• Most of the studies were limited to young autistic children, with very few looking at other groups (such as adults, females, individuals from ethnic minority groups).
• Some of the studies included participants with a range of disabilities and did not provide separate assessment and outcome data for those participants who were autistic .
• Some of the studies claimed to report positive results but sometimes the actual results were less positive. For example, the study by Carr and Felce (2007) showed that only five of the 24 children who received PECS actually made progress.  
• Some of the studies did not include measures for outcomes such as speech and other vocalisations.
• Very few of the studies investigated the effects of PECS in other areas such as academic skills
• Very few of the studies investigated all six phases of the PECS protocol and some did not report how well they followed the protocols established by Bondy and Frost.
• Very few of the studies compared PECS with other techniques or interventions which are designed to achieve similar results, such as sign language or voice output communication aids.
• Some of the studies did not state if PECS provided any beneficial effects which lasted in the medium to long term or in real world settings.
• One of the studies (Bondy and Frost, 1994) was a retrospective case series and undertaken by the researchers who developed the approach. 
• Most of the studies did not involve autistic people or parents and carers in the design, development and evaluation of the research.

For a comprehensive list of potential flaws in research studies, please see ‘Why some autism research studies are flawed’

Updated

17 Jun 2022

Last Review

01 Sep 2017

Next Review

01 Dec 2023