Table 1

Intraclass correlation coefficients SDQ subscales, overall and by ethnicity (n=17 006)

Variable	Ethnicity
	Overall*	Māori	NZ European	Pasifika	Asian
	r	r	r	r	r
Valid N	17 056	2677	10 735	1144	1169
Mean item correlations	0.282	0.237	0.315	0.130	0.210
Minimum item correlations	0.199	0.151	0.220	−0.009	0.055
Maximum item correlations	0.418	0.358	0.447	0.275	0.377
	ICC	ICC	ICC	ICC	ICC
Emotional Symptoms	0.126	0.067	0.186	0.017	0.098
Conduct Problems	0.137	0.112	0.179	0.038	0.079
Hyperactivity	0.174	0.136	0.245	0.050	0.122
Peer Problems	0.139	0.100	0.202	0.004	0.162
Prosocial	0.055	0.048	0.066	0.040	0.035
Mean ICC	0.126	0.093	0.175	0.030	0.099
Minimum ICC	0.055	0.048	0.066	0.004	0.035
Maximum ICC	0.174	0.136	0.245	0.050	0.162

SDQ, Strengths and Difficulties Questionnaire.
* Overall: all four ethnic groups combined
ICC: intraclass correlation coefficient