Table II.

Standardised ability scores of British Ability Scale tests measuring verbal ability at each wave, for children born after NC and ART.

BAS Verbal cognitive test score	NC	N	ART	N	Difference NC versus ART	P-value
BAS naming vocabulary (S2)	50.03	11 640	52.88	168	−2.85***	0.0007
BAS naming vocabulary (S3)	54.51	11 955	57.90	180	−3.38***	0.0000
BAS word reading (S4)	112.52	10 802	116.26	157	−3.83**	0.0035
BAS verbal similarity	59.14	10 496	60.08	150	−0.94	0.1234

*P < 0.05; **P < 0.01; ***P < 0.001 according to a two-tailed Student's t-test.

BAS, British Ability Scale.

Source: UK Millennium Cohort Study (MCS), wave 2–5, authors’ own calculations.