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Annual Report
Purpose: To verify and update information on the National Health Index (NHI) and to compile mortality statistics.
BDM disclosure to MoH: BDM provides child's names, gender, birth date, birth place, ethnicity and parents' names, occupations, birth dates, birth places, address(es) and ethnicities. BDM also indicates whether the baby was stillborn.
Compliance: Compliant.
Technical information
| Information matching provision | Births, Deaths, Marriages, and Relationships Registration Act 2021, s 112 |
| Year authorised | 2009 |
| Year commenced | 2009 |
| Programme type | Updating data |
| Unique identifiers | Birth Registration number, National Health Index Number |
System description
Each month Births, Deaths and Marriages (BDM) provide an encrypted file on CD to the Ministry of Health (MoH). MoH then requests the password, decrypts the file and adds it to their Working file. The extract file received from BDM is then deleted.
From this Working file an extract file of stillbirths is copied to be added to the Mortality Register for statistical reporting and research use.
The records in the Working file are then matched for both baby and mother records against the National Health Index (NHI) database. There are three types of results from this matching:
1) Any unique matches are accepted as correct and passed to the Match Results file.
2) Any records that give more than one potential match to an NHI record are manually matched, if possible, on the basis of the information in the NHI, and the match passed to the Match results file. If it is not possible to resolve the potential match, further investigation is undertaken and the NHI is updated as necessary.
3) For any records that do not return any potential matches MoH may choose to create an NHI record. Birth records that remain unmatched after a third attempt at matching, are deleted.
A reference file of linked baby and mother NHI numbers is created from the Match Results file. This is used to update the Maternity and Newborn Information System (MNIS) National Collection.
Then an NHI update file is created from the Match Results file. This update file is backed-up before being used to update the NHI. The back-up is retained as an authoritative data source for the NHI as MoH cannot currently prevent changes to the NHI by users.
The NHI is made available to external users and other agencies both in the form of direct access, and as update files.
Recent activity
| 2015/16 | 2016/17 | 2017/18 | 2018/19 | 2021/22 | 2022/23 | |
| Records received for matching | 60,248 | 59,373 | 61,390 | 59,479 | 60,789 | 59,063 |
| Matched | 60,240 | 59,373 | 61,378 | 59,476 | 60,780 | 59,009 |
| Not matched | 8 | 0 | 12 | 3 | 9 | 54 |
Possible matches result in the NHI record being verified or updated.
Not matched may include still births, multiple births and other cases where further investigation is required to ensure a correct match.
Birth information has been provided by BDM to the Ministry of Health from 1987, however, only since 25 January 2009 has this been treated as an authorised information match.
The utility of this provision was assessed in the report Superannuation and NHI Matches (January 2015) and again in Department of Internal Affairs, Government Super Fund, Ministry of Education, Ministry of Health, National Provident Fund and New Zealand Transport Agency information matching: review of statutory authorities for information matching (July 2020).
