Abstract: The aim of this paper is to detail the practical application of the Delphi technique as a culturally and clinically valid means of accessing expert opinion on the importance of clinical criteria. Reference is made to a bicultural New Zealand mental health nursing clinical indicator study that employed a three-round reactive Delphi survey. Equal proportions of Maori and non-Maori nurses (n = 20) and consumers (n = 10) rated the importance of 91 clinical indicator statements for the achievement of professional practice standards. Additional statements (n = 21) suggested by Delphi participants in round 1 were included in subsequent rounds. In round 2, participants explained the rating they applied to statements that had not reached consensus in round 1, and summarised responses were provided to participants in round 3. Consensus was considered to have been achieved if 85% of round 3 ratings lay within a 2-point bracket on the 5-point Likert-scale overall, or in one of the Maori nurse, non-Maori nurse, or consumer groups. A mean rating of 4.5 after round 3 was set as the importance threshold. Consensus occurred overall on 75 statements, and within groups on another 24. Most statements (n = 86) reached the importance benchmark. The authors conclude that when rigorous methods of participant selection, group composition, participant feedback, and determination of consensus and importance are employed, the Delphi technique is a reliable, cost-effective means of obtaining and prioritising experts' judgements.