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Data matching

Annual Report

Purpose: To compare the driver licence register with the electoral roll to:

  • identify people who are qualified to vote but have not enrolled, so that they may be invited to enrol
  • update the addresses of people whose names are already on the roll.


NZTA disclosure to Electoral Commission: NZTA provides the full name, date of birth and address of driver licence holders aged 17 and over whose records have not been marked confidential.

Compliance: Compliant.

Technical information

Information matching provision Electoral Act 1993, s.263B(3)(c)
Year authorised 2002
Year commenced 2002
Programme type Identifying unclaimed entitlement
Updating data

System description
The Electoral Commission uses the NZ Post Enrolment Service (ES) to operate  a set of five programmes designed to identify people who are eligible to vote but are not on the electoral roll (or whose enrolment details need updating). Those who are 17 years old are invited to enrol provisionally, in anticipation of when they turn 18. These programmes are:

  • • NZTA(driver licence)/EC Unenrolled Voters Programme;
  • • NZTA(vehicle registration)/EC Unenrolled Voters Programme;
  •  •MSD/EC Unenrolled Voters Programme (beneficiaries and students);
  • • DIA(Passports)/EC Unenrolled Voters Programme;
  • • Citizenship/EC Unenrolled Voters Programme


The files received are processed together in a sequence (NZTA drivers licences then NZTA vehicle registration, MSD (Benefits), Passports, MSD (Student loans) and finally Citizenship) intended to maximise the benefits from each run.

Drivers ⇾ Vehicles ⇾ Benefits ⇾ Passports ⇾ Students ⇾ Citizenship

The process for each of the matches is essentially the same.

1. The source agency creates an encrypted file extract from its records of people aged 17 and over who supplied their details in the period covered by the extract. Each extract includes full name, date of birth, address(es) and the date the record was last updated. This file is picked-up by ES staff.

2. ES matches each extract with the electoral database on the basis of surname, given name/s and date of birth.

3. The addresses for matched records are compared and if the addresses are the same, the records received for matching are deleted since the ES's records are, in effect, confirmed as current and no further action is needed.

4. Where the addresses differ, the 'update dates' are compared as ES need the most recent address. If the 'update date' from the source agency[1] is later than the 'update date' from the electoral roll record, and the ES does not have that address for that elector in their history, the details are saved to a correspondence file of individuals to be sent an invitation to update their details.

5. Random samples of 'possibly matched' records are examined manually to establish whether or not they should be regarded as matched. Where records appear to match, the process detailed in the previous paragraph is followed.

6. 'Not matched' records are saved to the correspondence file of individuals to be sent an invitation to enrol.

7. Before any invitation letters are generated, the correspondence file is sorted to eliminate duplicates. This internal check ensures that when a client record appears in more than one source agency file, only the first such record identified is used to generate a letter to the client. This prevents ES from sending multiple invitations to an individual. ES also maintains a record of information sent to it by the Registrar of Births, Deaths, and Marriages about deaths within the past five years. This is used to ensure that data matching correspondence is not sent to anyone who has died.

8. Records from the correspondence database are deleted when the electoral roll is updated for that elector, when ES receives notice of death or other special circumstances requiring that the person not be contacted again, or when it receives a 'gone no address' response that is not contradicted by more recent information.

The 'no response' category for these matches differs from other programmes in that no further action is taken in these matches if there is no response received. Non-response is not seen as a form of agreement and this programme requires a positive 'opt-in' response.

Recent activity

  2011/12  2012/13  2013/14  2014/15 2015/16
Match runs 4 4 3 3 3
Records compared 935,560 934,276 896,577 1,605,462 1,088,622
Invitations to enrol/update sent out 146,970 158,923 164,210 320,939 235,586
Presumed delivered 141,015 153,195 157,979 310,096 229,208
Enrolments (new and updated) 26,466 28,915 30,340 61,456 37,812
Percentage of letters
delivered resulting in changes
19% 19% 19% 20% 16%
No response 114,549 124,280 127,639 248,640 191,396
Cost $106,128 $116,894.39 $117,377 $228,995 $181,815
Average cost per enrolment $4.01 $4.04 $3.87 $3.73 $4.81

[1] The 'update date' supplied by the agency may be the last date the record was updated in any form, and does not necessarily relate to an updated address.