Developing the design of a continuous national health survey for New Zealand.

BACKGROUND: A continuously operating survey can yield advantages in survey management, field operations, and the provision of timely information for policymakers and researchers. We describe the key features of the sample design of the New Zealand (NZ) Health Survey, which has been conducted on a continuous basis since mid-2011, and compare to a number of other national population health surveys. METHODS: A number of strategies to improve the NZ Health Survey are described: implementation of a targeted dual-frame sample design for better Maori, Pacific, and Asian statistics; movement from periodic to continuous operation; use of core questions with rotating topic modules to improve flexibility in survey content; and opportunities for ongoing improvements and efficiencies, including linkage to administrative datasets. RESULTS AND DISCUSSION: The use of disproportionate area sampling and a dual frame design resulted in reductions of approximately 19%, 26%, and 4% to variances of Maori, Pacific and Asian statistics respectively, but at the cost of a 17% increase to all-ethnicity variances. These were broadly in line with the survey's priorities. Respondents provided a high degree of cooperation in the first year, with an adult response rate of 79% and consent rates for data linkage above 90%. CONCLUSIONS: A combination of strategies tailored to local conditions gives the best results for national health surveys. In the NZ context, data from the NZ Census of Population and Dwellings and the Electoral Roll can be used to improve the sample design. A continuously operating survey provides both administrative and statistical advantages.

The health of children in sole-parent families in New Zealand: results of a population-based cross-sectional survey.

OBJECTIVE: To investigate whether children in sole-parent families in New Zealand bear excess risks of poor mental and physical health relative to children in two parent families. DATA SOURCES AND STATISTICAL METHODS: The data source was the 2006/07 New Zealand Health Survey, a nationally representative household survey that sampled 502 children (5-14 years) of sole mothers and 1,281 children of partnered mothers. RESULTS: Children of sole mothers were 1.26 (0.94 - 2.69) times as likely as children of partnered mothers to return a low PhS score. Adjusting for maternal health and family socio-economic disadvantage eliminated this weak association (which in any case was of borderline statistical significance). Children of sole mothers were more than twice as likely as children of partnered mothers to return a low PsS score, adjusting for demographic variables only. CONCLUSIONS: There is only a weak negative association (if any) between sole-parenting and child physical health, but a stronger association with child mental health - consistent with most of the New Zealand and international literature. The association with child mental health is largely (but possibly not completely) 'explained' by the poorer mental health of sole-parents and the poorer socio-economic circumstances of single-parent families (on average). IMPLICATIONS: These findings support policies aiming to improve access of sole-parents and their children to community mental health services, and (more especially) policies aiming to ameliorate the disadvantaged economic circumstances of single parent families.

Psychiatric illness among a nationally representative sample of sole and partnered parents in New Zealand.

OBJECTIVE: To quantify the excess risk of specific, diagnosable mental illnesses experienced by sole parents in New Zealand, and to estimate the contribution of socioeconomic position (SEP), co-residence with other adults (as a proxy for social and practical support) and physical health status to this excess risk. METHODS: Data used in the present study were from the New Zealand Mental Health Survey, a nationally representative population-based household survey of 12,992 adults (16+ years) fielded in 2004. The sample included 1216 sole and 3681 partnered parents living with one or more dependent children, with an overall response rate of 73%. Mental illness (12 month prevalence of anxiety, mood, and substance use disorders, and suicidality) was measured with version 3.0 of the Composite International Diagnostic Interview. Illness severity was measured with the Sheehan Disability Scale and the Global Assessment of Functioning Scale. Covariates included household income from all sources, labour market attachment, co-residence with other adults and doctor-diagnosed chronic physical illness. Multiple logistic regression was then carried out on the weighted cross-sectional survey dataset. RESULTS: Adjusting for demographic variables, sole parents had significantly higher 12 month prevalences of mental illnesses than their partnered counterparts, with odds ratios (ORs) of 2.6 (95% confidence interval (CI)=2.0-3.3) for any mental illness, 2.9 (95%CI=2.1-4.0) for any serious mental illness, 2.2 (95%CI=1.7-2.8) for anxiety disorder, 2.6 (95%CI=2.0-3.4) for mood disorder, 3.6 (95%CI=2.2-6.0) for substance use disorder and 2.5 (95%CI=1.5-4.0) for suicidal ideation. Chronic physical illness accounted for only a small proportion of these excess risks. SEP and co-residence of another adult each explained approximately one-quarter of the excess risks and jointly explained approximately half (except for substance use disorders). Almost all of the effect of SEP was mediated by income, with employment status making only a very small independent contribution. CONCLUSIONS: The present results confirm the higher prevalence of mental illness experienced by sole parents, underlining the importance of improving access to primary mental health care, including alcohol and drug rehabilitation services, for sole parents. But they also caution against a solely clinical response and highlight a need to better understand and respond to the social and economic processes that lie behind the associations between mental health, socioeconomic position and sole parenthood in New Zealand.