Behavior Assessment System for Children Second Edition (BASC-2) The BASC-2 Parent and Teacher Rating Scale [55] items are organised into 9 clinical subscales: Aggression, Anxiety, Attention problems, Atypicality, Conduct problems, Depression, Hyperactivity, Somatization, and Withdrawal (as well as five adaptive scales). Hass et al. [65] showed that the BASC-2 had acceptable internal consistency for the 10 item aggression scale and the 9 item conduct problem scale with teachers as informants. There were also significant large differences between children with ASD and matched controls on the aggression scale (Cohen’s d = 0.58) and the externalising problems composite scale (Cohen’s d = 0.75). Mahan and Matson [70] also assessed known groups' validity of the BASC-2, with parents as informants. ASD children scored significantly greater than typically developing children on the conduct problems and externalising composite scales, but did not differ as expected on the aggression subsca...