Effects of phone versus mail survey methods on the measurement of health-related quality of life and emotional and behavioural problems in adolescents

Table 4 SDQ Test score distribution across modes of administration

	Mail		Phone		Δ-methods
					All	Girls	Boys	8-12	13-18
	Mean	SD	Mean	SD	effect size "d" ^{stat. sign Δ-Mean; stat. sign Δ-SD}
Children's self-report ^b	n = 528-530 ^a		n = 498		N = 1026-1028 ^a	N = 520-522 ^a	N = 504
Emotional	2.48	2.04	2.19	1.87	0.15^,	0.15^ns,ns	0.15^ns,ns	^d	^d
Conduct	1.87	1.28	1.65	1.24	0.17**^,ns	0.21*^,ns	0.13^ns,ns	^d	^d
Hyperactivity	3.48	2.15	3.39	2.16	0.04^ns,ns	0.10^ns,ns	-0.03^ns,ns	^d	^d
Peer Problems	2.07	1.54	1.78	1.33	0.20*^,	0.21^,	0.18*^,ns	^d	^d
Prosocial^c	7.70	1.59	8.22	1.61	-0.32**^,ns	-0.39**^,ns	-0.28**^,ns	^d	^d
Total	9.89	4.55	9.01	4.50	0.19**^,ns	0.23**^,ns	0.14^ns,ns	^d	^d
Parent's proxy-report ^b	n = 888-900 ^a		n = 791		N = 1679-1691 ^a	N = 833-839 ^a	N = 842-848 ^a	N = 657-662 ^a	N = 1022-1029 ^a
Emotional	1.57	1.70	1.64	1.85	-0.05^ns,ns	-0.06^ns,ns	-0.04^ns,ns	-0.13^ns,ns	0.01^ns,ns
Conduct	1.69	1.51	1.88	1.50	0.13**^,ns	0.11^ns,ns	0.14*^,ns	0.05^ns,ns	0.20**^,ns
Hyperactivity	2.76	2.26	2.77	2.31	-0.01^ns,ns	-0.01^ns,ns	0.01^ns,ns	0.02^ns,ns	-0.04^ns,ns
Peer Problems	1.43	1.68	1.26	1.47	0.11^,*	0.13^ns,**	0.09^ns,ns	0.12^ns,ns	0.11^ns,**
Prosocial^c	7.85	1.81	8.39	1.54	-0.31^,	-0.34^,	-0.31^,	-0.26^,	-0.35^,
Total	7.44	5.15	7.55	5.14	-0.02^ns,ns	-0.02^ns,ns	-0.02^ns;ns	-0.01^ns,ns	-0.04^ns,ns

^a Numbers vary due to missing values in the dimensions.
^b effect size classification: 0.20 = small; 0.50 = medium; 0.80 = large
^ns non significant; * p < .05; ** p < .01; first entry = t-test for mean differences; second entry = Levene test for SD-differences (all statistically significant SD-differences had the same direction as indicated by data-column 2 and 4)
^b Emotional = Emotional Symptoms; Conduct = Conduct Problems; Prosocial = Prosocial Behaviour; Total = Total Difficulties Score
^c Higher values indicate more strengths
^d SDQ self-report was administered for the 13-18 year olds only.

ISSN: 1471-2458