Defining migrants using travel histories and the 12/16-month rule

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Observing individual passengers’ sequences of border movements over time presents an opportunity for measuring changes in resident status that are based on actual patterns of stay in, or absence from, New Zealand.

Applying a measurement rule to individuals’ travel histories over time, to classify their migrant status, may produce different results from the passenger-type class determined by information they initially record on the passenger cards.

Based on passenger cards, currently, a person may transition from being reported as an ‘overseas visitor arrival’ to being reported as a ‘New Zealand-resident departure traveller’ if their stay is eventually 12 months or longer. For example, when the person transitions onshore from a short-term permit on arrival to extended permits or subsequent longer-term temporary resident-visa approvals. By doing this, they satisfy the period of residence in New Zealand required for classification as a New Zealand resident. Similarly, a New Zealand resident intending to make a short-term overseas trip may decide to live abroad for a longer time period than they report on their departure card.

Differences between actual travel histories, and reported intended stay or time away from New Zealand on the passenger cards that result in shorter or longer stays or absences, may affect the relevance or accuracy of the initial classification of migrant movements (using the passenger card information). This can result in estimates of migrant arrivals and departures being over- or under-reported when the passenger card is the primary information source used to determine migrant status.

Integrating passengers’ border movements over time enables us to observe their actual patterns of stay in New Zealand. An appropriate measurement rule applied to their travel histories allows us to classify migrant status as well as determine other passenger type categories (e.g. overseas visitor or New Zealand-resident traveller).

The new measure also introduces added opportunities for us to extend the measures of international migration statistics. For example, there may be interest in alternative measures of short-term as well as long-term migration. Further, traveller histories represent a longitudinal data source that enables other statistical measures of migration (eg return migration and step-migration).

Integration of individuals’ histories of migrant arrivals and departures classified by the 12/16-month rule with Stats NZ’s Integrated Data Infrastructure (IDI) also facilitates other analysis of migration trajectories and outcomes.


This report describes a new measure of determining the contribution of international migration to changes in New Zealand’s resident population. The measure uses linked travel histories and a rule for determining a change in resident status. This rule is independent of the individual’s legal residence status and also independent of the information stated on arrival and departure passenger cards.

We provide summaries of migrant arrivals and departures classified by the ‘12/16-month rule’, and include some comparisons with the official released figures of permanent and long-term (PLT) arrivals and departures.

We describe the operational rules underlying the 12/16-month rule for classifying migrant status. The paper also outlines the data integration process of border movements that is necessary for creating individuals’ travel histories, including a quality assessment of this process.

Citation Information


Defining migrants using travel histories and the 12/16-month rule


12/16 Month rule,

Alternate Title

travel histories and the 12/16-month rule




Statistics New Zealand




Migration, Migrants, Travel, 12/16-month rule

Coverage Information

Temporal Coverage

  • 2001-12 to 2014

Topical Coverage

  • Migration
  • 12/16 month rule
  • Travel Histories

Significant events impacting this study series

First Release 19 May 2017


11 Other

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Currently viewing revision 21 by on 29/08/2017 10:02:11 p.m.

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Revision 20
18/05/2017 10:47:50 p.m.


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