The psychometric properties of the Quantitative-Checklist for Autism in Toddlers (Q-CHAT) as a measure of autistic traits in a community sample of Singaporean infants and toddlers

Table 1 Comparison of key demographics between the Q-CHAT sample at 18 and 24 months and the full active GUSTO cohort

	18 months	24 months	Active GUSTO cohort n = 1089	Statistics (differences between 18 M Q-CHAT and active GUSTO)	Statistics (differences between 24 M Q-CHAT and active GUSTO)
	Q-CHAT	Q-CHAT
	n = 368	n = 396
Maternal age, years (SD)	30.3 (5.2)	30.5 (5.2)	30.8 (5.1)	t(367) = −1.75, p = .08, d = .10	t(395) = −1.29, p = .20, d = .06
Ethnicity
Chinese	195 (53.0 %)	232 (58.6 %)	616 (56.6 %)	χ ²(2) = 10.64, p = .01, w = .17	χ ²(2) = 7.35, p = .03, w = .14
Malay	119 (32.3 %)	113 (28.5 %)	277 (25.4 %)
Indian	53 (14.4 %)	51 (12.9 %)	196 (18.0 %)
Highest maternal education level
None/primary	14 (3.8 %)	16 (4.0 %)	42 (3.9 %)	χ ²(2) = 0.31, p = .86, w = .03	χ ²(2) = 0.15, p = .93, w = .02
Secondary/technical education	126 (34.2 %)	139 (35.1 %)	392 (36.0 %)
GCE ‘A’ levels/polytechnic/university/others	223 (60.6 %)	240 (60.6 %)	655 (60.1 %)
Household monthly income, SGD^a
0–999	9 (2.4 %)	8 (2.0 %)	22 (2.2 %)	χ ²(4) = 0.76, p = .94, w = .05	χ ²(4) = 0.11, p =1.00, w = .02
1000–1999	44 (12.0 %)	49 (12.4 %)	136 (13.3 %)
2000–3999	106 (28.8 %)	113 (28.5 %)	304 (29.8 %)
4000–5999	85 (23.1 %)	92 (23.2 %)	254 (24.9 %)
≥6000	102 (27.7 %)	114 (28.8 %)	303 (29.7 %)

^aAccording to the Department of Statistics Singapore, in 2013, median household income for Singaporean/Permanent Resident families with at least one working member was SGD7870

ISSN: 2040-2392