Using Mixed Methodology to Investigate ASD Diagnosis

Background:  ASD assessment can be complex and time consuming, and research has indicated that there can be wide variation in the age of diagnosis, with some individuals not receiving a diagnosis until later in childhood or even adulthood. The study presents information on the development of an evidence based methodology used, as part of a Scottish Government funded project, to identify the factors which may hinder or facilitate timely good quality diagnosis.

Objectives:  To develop a consistent mixed methodology for data collection regarding the process of ASD diagnosis across the age span in Scotland.

Methods:  Proportionate stratified sampling was used to identify a sample that was representative of the Scottish population. Part 1 of the project comprised a retrospective notes audit of 150 case notes and service interview of 8 child and 8 adult diagnostic services. In order to develop relevant factors, an Individual Data Collection Form and Service Configuration Tool were developed. The content was based on previous research, good practice guidelines, quality indicators and expert opinion. The evidence base was also examined to identify those factors which have been found previously to impact on: risk of ASD, referral for diagnosis of ASD and diagnosis of ASD. The tools were reviewed by practitioners with expertise in ASD assessment and piloted with case notes.   Part 2 of the project involved focus groups with the same 16 services, during which the diagnosing professionals created local action plans focused on improving the capacity of their service and the robustness of their diagnostic process.  These local action plans were aggregated into a national action plan.

Results:

The audit tools were found to:

• have good content, social and face validity;
• be easy to use in practice to gather relevant data.

 The tools were used to gather data relating to:

• the diagnostic pathway for individuals;
• the summary diagnostic pathway for services;
• factors influencing waiting times for diagnosis for adults and children.

 The focus groups:

• gave an effective opportunity for services to review and reflect on their performance;
• allowed comparison of diagnostic processes across Scotland;
• facilitated the development of local and national action plans for further improvement in ASD diagnosis.

 Conclusions:  The use of a mixed methods approach allowed for the collection of a rich detailed dataset pertaining to diagnosis of ASD, whilst also providing a useful method for services to reflect on their capacity and the robustness of their ASD diagnosis.