Fig. 1.

Receiver operating characteristic (ROC) curves for the Social Communication Questionnaire (SCQ): autism spectrum disorder (ASD) without phrase speech at 36 months.

(a) SCQ total (manual) score, area under ROC curve 0.88 (95% CI 0.84–0.92); (b) SCQ communication score, area under ROC curve 0.92 (95% CI 0.89–0.95); (c) SCQ social interaction score, area under ROC curve 0.95 (95% CI: 0.94–0.97); (d) SCQ repetitive behaviour score; area under ROC curve 0.67 (95% CI: 0.62–0.73). Includes all responders to the Norwegian Mother and Child Cohort 36-month questionnaire (n = 58 520). The sample includes 385 individuals with ASD: 86 without phrase speech at 36 months, 294 with phrase speech at 36 months, and 5 with missing information about phrase speech. For children with ASD without phrase speech, the communication score (b) includes the eight communication items that do not require phrase speech (items 20–25, 34–35). The social interaction score (c) includes the 15 social interaction items (items 9–10, 19, 26–33, 36–37, 39–40). The repetitive behaviour score (d) includes the seven repetitive behaviour items that do not require phrase speech (items 8, 11–16).