Aims: To investigate the patterns and criteria reported for categorisation of ethnicity in a sample of health research reports which made comparisons between Maori and non-Maori.
Methods: A total of 98 research reports, which made comparisons between Maori and non-Maori samples, were selected from the New Zealand Medical Journal over five 12-month periods and one 24-month period between 1980 and 1996.
Results: Only 19% of the 98 articles reported any information about the criteria used for categorising ethnicity. Only three articles mentioned how people of dual or multiple ethnicity were categorised. Although the term 'race' was commonly used in the 1980s, the terms 'ethnicity' and 'ethnic group' were more widely used later to describe ethnicity.
Conclusions: Much of the New Zealand research comparing Maori and non-Maori samples is likely to have unacknowledged error. Most articles did not meet minimum expected standards for reporting procedures for categorising ethnicity. There seemed to be little awareness of the major changes which have taken place in the New Zealand Census question concerning ethnicity between 1981 and 1996. Some suggestions were made for effective practice when assessing and reporting ethnicity in New Zealand research.