Different autism measures targeting different severity levels in children with autism spectrum disorder

The Childhood Autism Rating Scale™, Second Edition (CARS™-2) and Social Responsiveness Scale™, Second Edition (SRS™-2) are two measures for identifying autism symptoms. The CARS™-2 has two versions: Standard (CARS-ST) and High-Functioning (CARS-HF). To better understand their properties, this study aimed to investigate: (1) the associations among the CARS-ST, CARS-HF and the SRS™-2, and (2) the severity consistency between the CARS-ST and the CARS-HF. A sample of 125 children with autism spectrum disorder was recruited (mean age: 80.98 months, SD = 16.08). Based on Verbal Comprehension Index (VCI), children were divided into two groups: low severity level of autism spectrum disorder (LSL-ASD: VCI ≥ 80) and high severity level of autism spectrum disorder (HSL-ASD: VCI < 80). All children were evaluated with the CARS-ST and the SRS™-2, and the HF group, with the CARS-HF as well. In the LSL group, the CARS-ST and the CARS-HF had high correlation (r = 0.852, p < .001). Both versions had small to moderate correlations with the SRS™-2 (r = 0.130-0.491). In the HSL group, no significant correlations were found between the CARS-ST and SRS™-2 (p > .05). The CARS-HF and the CARS-ST had low severity consistency (Kappa = 0.376, p < .01). The CARS-ST and the CARS-HF had high correlations but low severity consistency. Different correlation patterns were found between the CARS™-2 and the SRS™-2 in the LSL and HSL groups. The results should help clinicians better understand the properties of the measures and choose appropriate measures when assessing autism symptoms.