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Table 4 Q-CHAT item descriptives at 18 (n = 368) and 24 months (n = 396) and test-retest reliability and differences between mean item scores at 18 and 24 months (n = 294)

From: 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

 

18 M

24 M

p***

Difference

Effect size of difference

Mean (SD)

Mean (SD)

z

r

1. Looks when name called

0.50 (0.7)

0.49 (0.7)

.49

−.37b

.02

2. Eye contact

0.62 (0.7)

0.56 (0.7)

.46

−1.43b

.08

3. Lines objects upa

1.72 (1.0)

2.13 (1.0)

.38

−5.57***c

.38

4. Understand child’s speech

2.07 (1.1)

1.59 (0.9)

.45

−5.88***b

.34

5. Protoimperative pointing

0.32 (0.7)

0.52 (0.8)

.27

−3.92***c

.23

6. Protodeclarative pointing

0.61 (0.9)

0.67 (0.9)

.40

−1.08c

.06

7. Interest maintained by spinning objecta

1.26 (1.0)

1.26 (1.0)

.42

−.30b

.02

8. Number of wordsa

2.71 (0.8)

2.01 (1.0)

.57

−10.69***b

.62

9. Pretend play

0.91 (1.0)

1.4 (1.2)

.37

−6.59***c

.38

10. Follows a look

0.86 (0.9)

0.99 (0.9)

.43

−2.66**c

.15

11. Sniffs/licks unusual objectsa

2.03 (1.3)

1.38 (1.2)

.32

−7.19***b

.42

12. Uses hand as toola

3.02 (1.2)

2.8 (1.2)

.28

−2.11*b

.12

13. Walks on tiptoesa

1.48 (1.2)

1.36 (1.0)

.51

−1.36b

.08

14. Adapts to changes in routine

0.95 (0.6)

1.01 (0.7)

.19

−1.64c

.10

15. Offers comfort

1.56 (1.2)

1.46 (1.1)

.57

−2.29*b

.13

16. Does same thing over and over againa

2.93 (1.1)

2.32 (1.3)

.44

−7.21***b

.42

17. Typicality of first words

0.99 (1.1)

0.72 (0.8)

.27

−3.76***b

.22

18. Echolaliaa

2.67 (1.2)

2.96 (1.2)

.38

−4.24***c

.25

19. Gestures

0.31 (0.6)

0.39 (0.7)

.36

−1.33c

.08

20. Unusual finger movementsa

1.49 (1.4)

1.19 (1.3)

.47

−3.30**b

.19

21. Checks reaction

1.24 (1.0)

1.34 (1.0)

.37

−1.45c

.08

22. Maintenance of interesta

1.16 (1.0)

1.33 (1.0)

.42

−1.91c

.11

23. Twiddles objects repetitivelya

2.14 (1.2)

1.54 (1.2)

.39

−7.59***b

.44

24. Oversensitive to noisea

1.44 (1.1)

1.29 (1.0)

.33

−1.66b

.10

25. Stares at nothing with no purposea

0.59 (0.9)

0.49 (0.84)

.35

−1.17b

.07

  1. *p < .05, **p < .01, ***p < .001 (all ρ correlations have p < .001 in this table)
  2. aReverse-scored items
  3. bWilcoxon signed-rank test z-scores based on positive ranks
  4. c z-scores based on negative ranks