Table 1.

Descriptive statistics of scores for all IQ subtests (standard scores unless otherwise stated).

	South Africa		UK		Post hoc (F)	Cohen’s d
	M	SD	M	SD
Similarities∗	8.12	1.40	14.22	3.04	437.69∗∗	2.58
Vocabulary∗	8.92	2.02	14.56	2.66	462.65∗∗	2.39
Information∗	10.19	3.21	11.75	2.72	32.57∗∗	0.52
Comprehension∗	8.99	2.50	12.48	2.59	163.36∗∗	1.37
Verbal Comprehension Index	94.81	10.25	120.12	14.84	311.68∗∗	1.98
Block Design∗	8.67	2.61	10.66	2.87	44.29∗∗	0.73
Picture Arrangement∗	8.33	2.82	10.08	2.26	43.486∗∗	0.68
Matrix Reasoning∗	10.68	2.37	10.59	2.71	0.10	0.04
Picture Completion∗	8.05	2.11	10.57	3.13	67.93∗∗	0.94
Perceptual Organization Index	94.28	10.94	103.09	14.69	40.57∗∗	0.68
Digit Symbol-Coding∗	9.75	2.51	7.72	2.68	49.40∗∗	0.78
Symbol Search∗	9.71	2.67	8.25	2.62	25.00∗∗	0.55
Processing Speed Index	98.18	12.27	88.99	13.20	41.51∗∗	0.72
Digit Span∗	9.35	2.26	9.50	2.94	0.20	0.06
Letter–Number Sequence∗	9.17	2.42	8.88	2.72	2.64	0.11
Arithmetic∗	8.66	2.53	9.58	3.14	0.17	0.32
Working Memory Index	93.83	11.40	95.45	14.09	<1.00	0.13
Verbal IQ	93.63	9.96	112.14	13.92		1.53
Performance IQ	93.56	10.05	98.89	13.94		0.44
Full Scale IQ Index	93.27	8.94	106.95	12.90		1.23

^∗Scale scores (M = 10, SD = 3); ^∗∗p < 0.001.