Table 2.

Sensitivity and specificity of the Social Communication Questionnaire (SCQ) at different cut-off levels (total n = 58 520)^a

	All children with ASD	Children with ASD without phrase speech	Children with ASD with phrase speech
SCQ total (manual) score ≥15b
Sensitivity (95% CI)	20 (16–24)	46 (35–57)	13 (9–17)
n/N	76/379	39/85	37/294
Specificity (95% CI)	99 (99–99)	99 (99–99)	99 (99–99)
n/N	56 977/57 738	56 977/57 738	56 977/57 738
Positive predictive value (95% CI)	9 (7–11)	5 (3–7)	5 (3–6)
n/N	76/837	39/800	37/798
Negative predictive value (95% CI)	99 (99–100)	100 (100–100)	100 (99–100)
n/N	56 977/57 280	56 977/57 023	56 977/57 234
SCQ total (manual) score ≥11b
Sensitivity (95% CI)	42 (37–47)	69 (58–79)	34 (29–40)
n/N	160/379	59/85	101/294
Specificity (95% CI)	89 (89–90)	89 (89–90)	89 (89–90)
n/N	51 637/57 738	51 637/57 738	51 637/57 738
Positive predictive value (95% CI)	3 (2–3)	1 (1–1)	2 (1–2)
n/N	160/6261	59/6160	101/6202
Negative predictive value (95% CI)	100 (100–100)	100 (100–100)	100 (100–100)
n/N	51 637/51 856	51 637/51 663	51 637/51 830
SCQ-33 score ≥12c
Sensitivity (95% CI)	25 (20–29)	64 (52–74)	13 (9–17)
n/N	93/379	54/85	37/294
Specificity (95% CI)	99 (99–99)	99 (99–99)	99 (99–99)
n/N	57 346/57 852	57 346/57 852	57 346/57 852
Positive predictive value (95% CI)	16 (13–19)	10 (7–12)	7 (5–9)
n/N	93/599	54/560	37/543
Negative predictive value (95% CI)	100 (99–100)	100 (100–100)	100 (99–100)
n/N	57 346/57 632	57 346/57 377	57 346/57 603

ASD, Autism spectrum disorder; SCQ-33, the 33 SCQ items that do not require phrase speech.

^a.Includes all responders to the Norwegian Mother and Child Cohort 36-month questionnaire (n = 58 520 including 385 individuals with ASD).

^b.The SCQ manual score was considered valid if there were ≤19 missing values on the SCQ items (available for 379 children with ASD).

^c.The SCQ-33 score was considered valid if there were ≤16 missing values on the 33 non-verbal SCQ items (available for 379 children with ASD).