Abstract
Report for for Public Health Intelligence, Ministry of Health, New Zealand.
The purpose of this paper is to discuss how Māori and non-Māori sample sizes in national surveys can indirectly contribute to the reduction, maintenance or even widening of inequalities in health. The paper was commissioned by Anne Duncan, Public Health Intelligence group of the Ministry of Health, as a result of debate about the sample frame for the New Zealand Health Survey 2002. The issues raised in this paper arise out of the experience of the Eru Pōmare Māori Health Research Centre in researching ethnic disparities in health.
The paper promotes the principle of ‘equal explanatory power’ – i.e. producing information for Māori health development to at least the same depth and breadth as that obtained for non-Māori health development. Good governance in an evidence-based policy environment compels us to ensure that data produced by the Crown is at least as productive for Māori as it is for non-Māori. For health surveys, a central requirement is to obtain enough Māori and non-Māori participants to explore potential explanations for disparities and develop effective strategies to address them. The simplest method is to seek equal numbers of Māori and non-Māori responders. The vision of the New Zealand Health Monitor is that its surveys have sufficient statistical power to analyse Māori data at the same degree of differentiation as non-Māori data (MoH 2002b). Although the 2002/03 New Zealand Health Survey will not achieve equal explanatory power, it is timely to consider the implications of Māori and non-Māori sample size for future surveys.