In the first study of its kind, a survey of National Hauora Coalition (NHC) general practice clinics conducted in 2017 found that only 13% of Māori enrolments had Iwi data recorded. Of the 33 clinics included in the study, 27% sought Iwi name/s by way of a specific question on their enrolment form. Six different questions regarding Iwi were used by these clinics. The largest Iwi group recorded by NHC clinics was Ngāpuhi. The authors stated that their study helps to highlight systematic problems contributing to continued restrictions to self-determination for Māori.