COUNTING FOR NOTHING: UNDERSTANDING THE ISSUES IN MONITORING DISPARITIES IN HEALTH.

INTRODUCTION(2)

Disparities between New Zealanders, especially Maori and non-Maori, have become an area of significant policy focus. It is largely academic whether interest has sharpened because of the Treaty of Waitangi, a commitment to equity and social justice, the government priority to reduce disparities, or indeed combinations of these. A far more pressing issue is the quality of data to support policy development, monitor disparities and inform interventions.

While disparities are always of concern they are particularly poignant in health as, at the extreme, they represent differential access to the benefits and privileges of our society, reduced ability to contribute to future generations and premature death.

Most policy makers are aware of the challenges faced in the classification of ethnicity, which underpins the measurement of disparities. Many are also aware that changes in the ethnicity question in the 1996 Census and the notification of births and deaths have led to inconsistencies which undermine the health time series. However, few options have been proposed for monitoring trends in health disparities between Maori and non-Maori during the decade of the 1990s.

The purpose of this paper is to background these issues, describe recent changes and their relative influence, and to reiterate the need to monitor disparities in health during the 1990s despite these challenges.

BACKGROUND

Fundamental to this discussion is the definition of who is Maori, and who decides on the definition. The word "Maori" means normal, usual and ordinary (Williams 1992:179). It is an adjective used to describe things in their natural state. Broughton (1993:506) notes:

In this way, the word "Maori" was used to describe the indigenous people of the land, that is, to refer to the ordinary inhabitants of Aotearoa. However, while "Maori" began as a definition which accepted tangata whenua status as normal, the early government definition of Maori was "persons greater than half Maori blood" and Maori-European "half-caste" living as Maori, i.e. "living as members of Maori tribes", and it later evolved to "persons of half or more Maori blood" (Department of Statistics 1988:44-45).

Those reviewing Maori population growth using fertility, mortality and intermarriage patterns were concerned that more people were identifying themselves as Maori than was predicted by demographic trends. The Review Committee on Ethnic Statistics reflected that even in the 1926 Census a large proportion of Maori "overstated their degree of Maori blood" and that many people who were Maori by self-definition, but who also had significant non-Maori ancestry, stated that they were one-half Maori or more.

Thus, this suggests that since at least the turn of the century, the biological definition of Maori (i.e. half or more Maori blood) has not been interpreted as intended by a considerable proportion of the Maori population. (Department of Statistics 1988:46) So despite government definitions, Maori reclaimed the ability to name ourselves as Maori. In the 1970s, Maori expressed a desire for statistics to be more inclusive in counting who is Maori. The Maori Affairs Amendment Act (1974) broadened the definition of Maori to include all descendants of Maori. At the same time, the Department of Statistics began considering concepts of ethnicity and cultural affiliation. Based on the way people define themselves and the group(s) to which they feel most closely aligned, these concepts reflected Maori practice (Department of Statistics 1993). Ethnic group has been defined as follows:

The term ethnic group has a wide meaning. It is not the same as nationality, race or place of birth. Ethnic groups are.., people who have culture, language, history or traditions in common. These people have a "sense of belonging" to the group, which may not be based on birth. It is possible to belong to more than one ethnic group. At different times of their life people may wish to identify with other groups. (NZHIS and Ministry of Health 1996) The subsequent change of definition of Maori in the census, from one based on descent prior to 1986 to one of cultural affiliation based on self identity from 1986, could be seen as a realignment of official statistics to a Maori reality.

DISPARITIES IN HEALTH

Commentary on health outcomes is usually based on consideration of rates. This involves knowledge of the frequency of events within a certain population at or over a specified period of time. For example, lung cancer mortality among Maori women in 1996 would be expressed as the number of Maori women dying of lung cancer in that year (the numerator) derived from the health and vitals datasets, as a proportion of the number of Maori women in the population in 1996 (the denominator) derived from the census. This underlines the importance of understanding the derivation of the various data, how they are collected, the quality of data and the impact of any changes to these over time.

Denominators

Data for denominators are usually derived from census information. There are three key issues in census data:

* Firstly, the change in 1986 from a biological, descent-based definition to one based on ethnicity.

* Secondly, with this change came the opportunity to capture multiple ethnicities and distinguish between those who give Maori as their only ethnic group (sole Maori) and those who give Maori as only one of their ethnic groups (mixed Maori). Together these two make up the Maori ethnic group (MEG).

* Thirdly, there have been changes to the question seeking to establish the Maori population in the last five censuses. In each of the last three censuses a different ethnicity question has been used.

In 1986, the question simply asked: "What is your ethnic origin? Tick the box or boxes which apply to you." (See Figure 1.)

[Figure 1 ILLUSTRATION OMITTED]

In 1991, the question was changed, as it was believed that the word "origin" was too closely aligned with the concept of ancestry. It used "Which ethnic group do you belong to?" with the same rider. (See Figure 2.)

[Figure 2 ILLUSTRATION OMITTED]

In 1996, there was a significant change to the wording of the question (in line with all questions in that census) and more categories were given. (See Figure 3.)

[Figure 3 ILLUSTRATION OMITTED]

In the 1996 Census, more New Zealanders, including Maori, gave multi-ethnic responses. Subsequent research has shown that the wording of the 1996 question, and especially the extra categories for "other European", likely encouraged multiple responses. Further, these responses were more likely to be based on ancestry than were responses to the 1991 Census ethnicity question (ACNeilsen 1999). Consequently, the 1996 "sole Maori" group is significantly smaller than expected and the "Maori ethnic" group larger. It is likely that some who gave a "sole Maori" response to the 1991 question gave an ancestry-based multi-ethnic response to the 1996 question. Furthermore, some people of Maori ancestry who previously had not identified Maori ethnicity, seem to have been encouraged by the 1996 question to add Maori to their ethnicities.

So, four Maori populations have been described by census data in the latter half of this century:

* half or more Maori blood prior to 1986;

* sole Maori ethnicity (those who identify Maori as their only ethnicity) from 1986;

* the Maori ethnic group from 1991 (those who state Maori as one of their ethnic groups and includes sole Maori);

* the Maori ancestry group...