First, screening questionnaires (links to them are in the original post). I'll outline the basics. Ask questions if necessary.
The Autism Spectrum Quotient (AQ)
This is the main one. It's used to measure the degree of autistic traits in adults of average and above intelligence, including in the general population. People with social anxiety or OCD have elevated scores on this, generally in between controls and those with AS/HFA.
The main studies are here
, and there are others. 80% of adults with AS/HFA scored 32 or above, whereas only 2% of controls did. They recommend those with elevated scores of about 26 or above and troubling symptoms should consider an ASD assessment.
The Empathy Quotient (EQ)
This can be read about here
. Empathy allows us to tune into another's thoughts and feelings and understand their intentions and predict behaviour. It also produces a corresponding emotion in the observer. It's a multifaceted construct and certain patterns of impairment are found in other psychiatric groups (such as a specific emotional empathy impairment in psychopathy).
81% of adults with AS/HFA scored 30 or less, whereas only 12% of controls did. Scores might be reduced if you're depressed for instance.
The Systemising Quotient (SQ)
This measures the drive to understand the rules governing the behaviours of systems and the drive to construct them.
The studies are here
, and here
(the latter ones are in combination with the EQ).
Adults with AS/HFA have a mean SQ-R score of 77.2 (standard deviation 23.8 ). Adult control males have a mean score of 61.2 (standard dev. 19.2). Adult control females have a mean score of 51.7 (standard dev. 19.2). There are large overlaps.
On the testing page (and explained in detail in the 2nd study above) you can determine to what extent you have an empathising and systemising style. Most people are quite balanced. More individuals with AS/HFA have the extreme S brain type.
Reading the Mind in the Eyes test
This is another test with large overlaps with control groups. See study here
(and others). (This test was also used on psychopaths here
and their overall score didn't significantly differ from the control group score, indicating no theory of mind impairments.)
The 15 AS/HFA male adults scored a mean of 21.9 (standard deviation 6.6). The general population controls scored a mean of 26.2 (standard dev. 3.6), and the IQ matched controls scored a mean of 30.9 (standard dev. 3.0).
In the psychopath study, the mean score was 23.9 (standard dev 5.3) and the mean score for the control group was 26.3 (standard dev 4.3).
It's also worth looking up the Reading the Mind in Film
test (see the Cambridge Autism Research Centre test page to download it). This is much better at simulating real life where you have to integrate multimodal cues. Those with AS who score normally on simpler cue reading tests are likely to score low on this. It's thought to be due to underconnectivity in the autistic brain, making them poorer than controls at integrating socioemotional information. It also discriminates well, apparently placing over 90% of participants in their correct groups (either AS/HFA or control) based on their score alone. There are several other tests using film rather than static images, though not available online. In general they are much better at detecting social cognition deficits in intelligent AS adults than static or single mode cue tests.
Plots showing the overlaps between those with AS/HFA and control groups can be seen for each instrument below (taken from the above papers). The spread in the AS/HFA group for reading eyes indicates a larger spectrum of ability than controls. To enable visual comparison, I overplotted this in red onto the published plot for the general population and student control groups. This isn't the entire AS/HFA range, though, but just the standard deviation (about 68% of the sample who are closest to the AS/HFA average, assuming a normal distribution).
S. Baron-Cohen, S. Wheelwright, R. Skinner, J. Martin and E. Clubley, (2001) The Autism Spectrum Quotient (AQ) : Evidence from Asperger Syndrome/High Functioning Autism, Males and Females, Scientists and Mathematicians Journal of Autism and Developmental Disorders 31:5-17
S. Baron-Cohen and S. Wheelwright, (2004) The Empathy Quotient (EQ). An investigation of adults with Asperger Syndrome or High Functioning Autism, and normal sex differences Journal of Autism and Developmental Disorders 34:163-175
S. Wheelwright, S. Baron-Cohen, N. Goldenfeld, J. Delaney, D. Fine, R. Smith, L. Weil and A. Wakabayashi, (2006) Predicting Autism Spectrum Quotient (AQ) from the Systemizing Quotient-Revised (SQ-R) and Empathy Quotient (EQ) Brain Research 1079:47-56
Mind in Eyes test
S. Baron-Cohen, S. Wheelwright and J. Hill, (2001) The 'Reading the mind in the eyes' test revised version: A study with normal adults, and adults with Asperger Syndrome or High-Functioning autism Journal of Child Psychology and Psychiatry 42:241-252