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Assistance Dogs and Autism Ranking: Insufficient/Mixed evidence

Status Research

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

Type of study

Some studies used relatively weak methodologies or did not adequately describe the methodologies they used. For example

  • Three of the studies (Burgoyne et al, 2014; Burrows et al, 2008; Smyth and Slevin, 2010) used qualitative, non-experimental methodologies. That is, they did not control the introduction of the dogs to the families nor did they use any kind of pre-post-test to assess whether there was a measurable difference before and after the dogs were introduced. 
  • Three of the studies (Burrows et al, 2008; Smyth and Slevin, 2010; Viau et al, 2010) used single-case designs, that is, they did not have a control group of participants who did not receive an assistance dog.
  • Neither of the two randomised studies (Fecteau et al, 2017; Groomes et al, 2014) described the randomisation process. This means that we do not know if the participants in these studies were randomised or if they were randomised in an adequate manner.
  • None of the group studies were blinded, which means that the participants in each group knew whether they had an assistance dog, which could have affected the results of the study.

Participants

Some studies had limited numbers of participants, selected participants in ways that could have biased the outcomes or did not adequately describe the participants or how they were selected. For example

  • Two of the studies had very few participants.  For example, the study by Smyth and Slevin (2010) had only seven participants, the study by Burrows et al (2008) had only 10 participants and the study by Groomes et al (2014) had only 14 participants. 
  • All of the studies were restricted to specific groups of autistic participants, such as children and young people (although this may be reasonable given that assistance dogs are not normally available to adults on the autism spectrum).
  • Most of the studies did not independently verify the diagnosis of autism using established tools like the ADOS.  
  • Most of the studies did not provide enough details about the participants (such as the ratio of males to females, their intellectual and verbal abilities, their ethnicity, or whether they had any co-occurring conditions that could have affected the outcomes).
  • Most of the studies did not clearly state all the inclusion and exclusion criteria for participants (such as age, coexisting conditions, coexisting treatments etc.).

Intervention/s

Some of the researchers delivered the interventions in ways that could have biased the outcomes or did not adequately describe how the interventions were delivered. For example,

  • Some of the studies did not provide enough information about the assistance dogs and how they were used, so that other researchers could understand what was being delivered and how. For example, some studies did not describe the age or breed of dog, did not describe the training that the dogs undertook before they were placed with the family, did not describe the training that the parents undertook before they received the dog etc.
  • Some of the studies ran for relatively short periods of time. For example, the study by Viau et al (2010) ran for only four weeks and the study by Groomes et al (2014) ran for only six weeks.
  • Some of the studies ran for a relatively long period (over a year) meaning that any changes in the participants could have been due to their natural development rather than the intervention.
  • Some of the studies included participants who probably received one or more other interventions (such as speech and language therapy or a medication) at the same time as they had the dog but did not describe or allow for these.

Comparators

Some group studies did not compare like with like or did not provide enough detail about any differences in the experimental and control groups and the interventions each received. For example,

  • The study by Groomes et al (2014) did not provide enough details about the participants in the control group (such as the ratio of males to females, their intellectual and verbal abilities, their ethnicity, or whether they had any co-occurring conditions that could have affected the outcomes).
  • The same study did not provide enough details about the intervention (social skills training programme) received by the control group.  (In fact, the experimental group also received this programme, in addition to having access to an assistance dog, but it was not clearly described for either group.)
  • The other two group studies (Burgoyne et al, 2014; Fecteau et al, 2017) used a wait-list control group (who received nothing) rather than an active control group (who would have received an active intervention of some kind, such as a robotic dog).

Outcomes and Measures

Some researchers did not use the most appropriate outcome measures or did not adequately describe those outcome measures and any limitations they might have had. For example,

  • Some of the studies did not provide enough detail for us to be able to make a considered assessment of their efficacy. For example, the study by Groomes et al (2008) stated that assistance dogs “may provide a means of helping adolescents and family members to employ pro-social behaviors” but they did not state what those pro-social behaviours were.
  • The same study stated that it used a range of outcome measures inc. the Multidimensional Anxiety Scale for Children, the Adaptation to Disability Scale-Revised and the Autism Social Skills Profile (ASSP) but failed to provide any data from those measures. 
  • One of the studies (Fecteau et al, 2017) used the Childhood Autism Rating Scale to assess the behaviours of the children at the beginning of the study but did not use it to assess the children at the end of the study, which would have been quite useful, as it could have shown if the dogs had produced any effect in the children.
  • Some of the studies (such as Burgoyne et al, 2014) used self-reports and parents’/guardians’ personal perceptions rather than any kind of objective measures.
  • One of the studies (Viau et al, 2010) used an objective outcome measure (cortisol awakening response, a marker for stress) but noted that it was unclear what changes in the marker meant in practice. 
  • None of the studies appeared to use any kind of adverse effect measure to test whether the dogs produced any adverse effects.

Data Analysis

Some researchers did not use the most appropriate statistical tools and techniques to analyse the data from their studies or did not adequately describe those tools and techniques and any limitations these may have had.

  • Some of the studies had incomplete data. For example, Viau et al (2010) noted that there were some difficulties in collecting some of the saliva samples resulting in a loss of data.  
  • Some of the studies did not provide any kind of statistical analysis of the outcomes (such as the statistical significance) and none of the studies provided any data on the effect sizes. 
  • The study by Groomes et al (2008) stated that the results approached statistical significance but did not provide any data to demonstrate this.
  • Some of the studies did not record if the assistance dogs had any beneficial or harmful effects in the medium (three to six months) or longer term (six months or longer).

Other

Some research studies included other flaws that could have biased the outcomes. For example,

  • None of the studies appeared to involve people on the autism spectrum in the design, development and evaluation of those studies.
  • The study by Burrows et al (2008) was funded in part by National Service Dogs (a supplier of assistance dogs) and the study by Viau et al (2010) was funded by La Fondation MIRA (a supplier of assistance dogs). The researchers involved may therefore have been biased towards the assistance dogs, however unconsciously.

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

Updated
31 Jan 2019
Last Review
01 Jan 2019
Next Review
01 Jan 2022