A white paper for clinicians, researchers, educators, and healthcare
administrators on the application and significance of the Childhood
Autism Rating Scale, Second Edition (CARS-2).
The CARS-2 is a standardized, clinician-administered rating scale that evaluates the presence and severity of autism-related behaviors. The second edition modernized the tool by expanding its applicability across age groups and functioning levels, making it a cornerstone of early identification.
The total score, ranging from 15 to 60, indicates the severity of autism spectrum disorder symptoms. Scores must be interpreted by trained clinicians and supplemented with developmental history and additional diagnostic assessments for an accurate diagnosis.
CARS2-ST (Standard)
For children under 6 or with lower cognitive functioning.
CARS2-HF (High Functioning)
For verbally fluent, cognitively able children.
CARS2-QPC (Questionnaire)
Gathers input from caregivers.
Supplemental Tools (e.g., ADOS-2)
Used in combination for a holistic diagnosis.
Psychometric Strength: Research consistently demonstrates strong reliability and validity for the CARS-2, with high inter-rater reliability and strong correlations with gold-standard tools like ADOS-2. It is effective for distinguishing ASD from other disorders.
Early identification of autism is crucial for improving long-term outcomes. The CARS-2 is highly effective for early detection because it relies on observable behaviors, captures subtle early indicators in toddlers, and provides quantitative severity levels that are helpful for determining service eligibility. It is rarely used in isolation and is commonly paired with other diagnostic tools.
| Domain type | Sub-domain | Score |
|---|---|---|
| Core Symptom Domains | Relating to People | 3 |
| Core Symptom Domains | Imitation | 2.5 |
| Core Symptom Domains | Verbal Communication | 3.5 |
| Behavioral & Sensory | Adaptation to Change | 35 |
| Behavioral & Sensory | Body Use | 28 |
| Behavioral & Sensory | Activity Level | 15 |
| Aspect | Description |
|---|---|
| Highly Reliable | High inter-rater reliability. |
| Clinically Valid | Strong correlation with gold-standard tools. |
Clinical Research Group
The CARS-2 remains one of the most practical and powerful tools for identifying autism and guiding early intervention decisions. Its reliable structure, clinician-friendly format, and strong research foundation make it essential in developmental evaluation settings. When combined with additional assessments and expert clinical judgment, it provides a robust foundation for accurate diagnosis and effective intervention planning
