The four ASD assessments
Background
Within the 3di's autism provision, there are four different assessments:
ICD-10 ASD extended
ICD-10 ASD brief
DSM-5 ASD extended
DSM-5 ASD brief
In total the 3di has a bank of nearly 900 questions, all of which are listed in the Interview Explorer. However, in typical usage you will answer only a much smaller set of questions drawn from this bank, known as a route. Each ASD assessment has its own route, scoring algorithm, and a set of scoring tables in the Word reports.
The four assessments were added to the software successively over 25 years of research and use. Depending on when you trained, not all of the assessments may be available in your software. We encourage you to use the latest DSM-5 assessments, but each new version of the 3di includes the previous assessments too.
The ASD routes contain only those questions which contribute to the scoring tables in the report. They do not contain the qualitative questions about the child's family, medical and educational history. For a richer report, you can complete these in advance using pre-entry, or during the interview via the Interview Explorer.
The ASD assessments today
1. ICD-10 extended
This was the first ASD algorithm implemented in the 3di, around 2004. Its scoring is based on 134 questions. The corresponding route is ASD_extended (ICD-10).
This original 3di assessment was published in The developmental, dimensional and diagnostic interview (3di): a novel computerized assessment for autism spectrum disorders.
In current 3di versions, if you still want to see ICD-10 report components, visit the Preferences form. The output of this algorithm appears only in the extended Word report, and not in the brief Word report. In the extended Word report the corresponding tables appear under the heading ICD-10 ASD.
In older 3di versions, prior to the introduction of the DSM-5 assessments, ICD-10 extended was known simply as ASD_extended, or even just 3di.
2. ICD-10 brief
This was the second ASD algorithm implemented in the 3di, around 2009. Its scoring is based on 61 questions. The corresponding route is ASD_brief (ICD-10).
The derivation and validation of this assessment was published in The construction and validation of a short form of the developmental, diagnostic and dimensional interview.
In current 3di versions, if you still want to see ICD-10 report components, visit the Preferences form. The output of this algorithm appears only in the brief Word report, and not in the extended Word report. In the brief Word report the corresponding sections appear under the heading ICD-10 ASD.
In older 3di versions, prior to the introduction of the DSM-5 assessments, ICD-10 brief was known simply as ASD_brief or sometimes 3di-sv for '3di short version'.
3. DSM-5 extended
This was the third ASD algorithm implemented in the 3di, around 2013. Its scoring is based on 177 questions. The corresponding route is ASD_extended (DSM-5 Crit A + B).
This output of this algorithm appears only in the extended Word report, and not in the brief Word report, under the heading DSM-5: ASD extended assessment.
4. DSM-5 brief
This was the fourth ASD algorithm implemented in the 3di, in 2022. Its scoring is based on 66 questions. The corresponding route for this algorithm is named ASD_brief (DSM-5 Crit A+B).
This output of this algorithm appears in both the brief and extended Word reports, under the heading DSM-5: ASD brief assessment.
Reference for the scoring algorithms
Details of the algorithms 1 and 2 and our amalgamation of ICD-10 and DSM-4 are explained in three files found in the 3di installation folder under the Reference subfolder. ASD_three-domain_scales_defined and ASD_diagnosis_flowcharts_3_domain describe the algorithm and how a diagnostic outcome is arrived at, while ASD_scales_Ref details which individual questions contribute to each subscale.
Details of the DSM-5 algorithms 3 and 4 are explained in two files found in the 3di installation folder under the Reference subfolder. DSM-5_ASD_scoring describes the algorithm, while ASD_scales_Ref details which individual questions contribute to each subscale.
3di-adult
You may have heard about this assessment. The 3di-adult was a standalone, pen-and-paper tool developed as part of a research project which drew on the 3di question bank but was never implemented in the software, and presently there are no plans to do so. You can read the paper here.
The 3di software is currently not suitable for the assessment of adults.
History of the assessments
The 3di was initially developed as a research tool starting around 1998 at the Great Ormond Street Institute of Child Health under the direction of Professor David Skuse. The World Health Organisation's International Statistical Classification of Diseases and Related Health Problems, 10th revision, or ICD-10, came into effect in 1993. Meanwhile the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, fourth edition, or DSM-IV, was published in 1994. The 3di treated the two systems as broadly equivalent, and the 3di's first ASD assessment was built around an amalgamation of ICD-10 and DSM-IV criteria.
The first autism assessment in the 3di, now known as the ICD-10 extended, contained 134 questions, and was designed for research use where there was sufficient time for such a thorough assessment.
Over the following years, demand grew for a quicker autism informant interview for use in CAMHS clinics where there was less time available. This led to the development of the ICD-10 brief assessment.
DSM-5 came into effect in 2013, followed by ICD-11 in 2022. The 3di was updated with a new DSM-5 extended assessment for autism in 2013. Finally in late 2022 the DSM-5 brief assessment was released.
Comparing DSM-5 and ICD-11, we consider that by design the two sets of criteria are so similar that ASD outcomes (and many others) can be reported as DSM-5 or as ICD-11. The 3di always references DSM-5 because the APA got there many years before the WHO; you can substitute one term for the other in your reports or perhaps reference neither.
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