Table 1.

Summary of basic statistics relating to child development scores using questionnaire measures.

Age	Score	No. tested	Range	Median	Mean [SD]
6 m	Social skills	11354	0–30	17	17.23 [4.86]
Fine motor	11359	0–33	21	21.13 [6.36]
Communication	11355	0–24	16	16.44 [2.97]
Gross motor	11394	0–39	16	16.42 [5.93]
Total	11348	6–126	70	71.23 [15.57]
18 m	Social skills	11087	0–28	19	19.15 [3.89]
Fine motor	11090	0–32	27	26.69 [3.06]
Communication	11102	0–28	16	15.94 [4.79]
Gross motor	11087	0–22	20	19.45 [2.88]
Total	11067	4–110	82	81.25 [10.78]
30 m	Social skills	10260	0–26	19	18.94 [3.76]
Fine motor	10286	0–32	27	26.37 [3.76]
Gross motor	10272	0–22	20	19.51 [2.52]
Total	10244	0–80	66	64.87 [7.82]
42 m	Social skills	10014	0–26	23	22.10 [3.14]
Fine motor	10019	0–34	31	29.72 [4.06]
Gross motor	10026	0–30	27	26.35 [3.59]
Total	10011	0–90	80	78.19 [8.83]