Examination of the cut-off scores determined by the Ages and Stages Questionnaire in a population-based sample of 6 month-old Norwegian infants

Table 4 Cut-off scores in the present dataset and in the US and the Norwegian reference samples, and percentage of infants in the present dataset scoring at or below the various cut-off values

				Percentage scoring at or below
	Dataset 2.5 perc/N	US Cut-off N = 633	N.ref. Cut-off/N	Dataset 2.5 perc	US Cut-off	N.ref. Cut-off
Communication	25/1048	29.65	25/169	4.6%	4.6%	4.6%
Gross motor	15/1052	22.25	15/169	5.3%	12.2%	5.3%
Fine motor	18/1044¹ 20/1044¹	25.14	25/166	18¹ = 2.6% 20¹ = 11.0%	21.2%	21.2%
Problem solving	25/1047	27.72	30/169	2.6%	2.6%	5.4%
Personal social	20/1050	25.34	20/169	3.0%	6.2%	3.0%
Scoring at or below at least one area				18¹ = 13.8% 20¹ = 20.5%	33.8%	30.3%

Recommended Cut-off scores in the US (Mean - 2SD) and Norwegian manual (primarily based on the 2 percentile) in the areas of Ages and Stages Questionnaire 6-months old, and 2.5 percentile in the present dataset (equivalent to a cut-off value at mean - 2SD, most areas had a skewed distribution)
¹: The 2.5 percentile was 18 using the coding according to the US User guide 2, and 20 using coding according to the Norwegian manual (due to scores not ending on 0 or 5 to be rounded to the closest 0 or 5)

ISSN: 1471-2431