Age distribution of children migrating to New Zealand

The 12-16 month rule is a way of defining passengers based on border movements.
A traveller who did not live here previously is considered a long-term migrant arrival if they have spent 12 of the following 16 months in New Zealand. A traveller who previously lived in New Zealand, but who spent 12 of the next 16 months out of New Zealand is classified as a long-term migrant departure.
Net migration: long-term arrivals minus long-term departures.

From early 2022, some governments, including New Zealand, relaxed these restrictions, allowing more people to cross their borders. From 1 August 2022, New Zealand’s border opened to all visitors and international students.
Since January 2020, governments have imposed international travel restrictions in multiple countries, due to the spread of COVID-19 around the world. In March 2020, the New Zealand government introduced further measures to protect New Zealanders from the COVID-19 virus, effectively limiting travel to New Zealand and travel within New Zealand.

http://datainfoplus.stats.govt.nz/Item/nz.govt.stats/f705ca38-ea6e-453f-b1d9-a95dc0fcaf59?_ga=2.137435637.439961159.1550529916-321851374.1528776322#/nz.govt.stats/d83affa2-c0e1-4629-9aff-cc8452eb41c6#
https://www.stats.govt.nz/methods/defining-migrants-using-travel-histories-and-the-1216-month-rule

With this new approach it takes 17 months before final migration estimates are available. To produce timely results, Stats NZ use a statistical model to produce provisional migration estimates. Statistics produced using these provisional estimates have uncertainty for 16 months; after this time the classification of all border crossings can be finalised.

Previous to May 2017 international migration data was reported based on departure cards. A change to an outcomes based measure of migration (which uses passport data to link arrivals and departures and accurately measure how long people spend in, or out of, New Zealand after their initial border crossing. To classify a border crossing as a migrant movement, we need to observe up to 16 months of travel history.) has enabled the removal of the departure card when travelling out of New Zealand.

The previous migration measure (permanent and long-term (PLT) migration) was estimated from travellers’ statements on arrival or departure cards – based on how long they intended to stay in New Zealand (or be away). This intentions-based measure was timely; however, traveller behaviour was not always consistent with the stated intentions at their border crossing. This may be due to: circumstances changing, misunderstanding the questions on the traveller cards and incorrectly reporting their intentions, or deciding to extend their visa or stay/absence.

The outcomes-based measure is estimated from the actual travel histories of people travelling in and out of New Zealand. This provides a more accurate measure of migration – whether they are a migrant is based on their actual movements.

At link provided select: Tourism > International Travel and Migration - ITM > Estimated migration by direction, age group and sex, 12/16-month rule (Annual-Dec).
All variables were selected to create this dataset.

International migration statistics give the latest outcomes-based measure of migration, which includes estimates of migrants entering or leaving New Zealand.

To measure changes in New Zealand resident status based on actual border movements.

International Migration statistics are based on electronic arrival and departure records for each passenger supplied to Stats NZ by the New Zealand Customs Service. These electronic records include flight and passport details, such as date of travel, date of birth, sex, and country of citizenship.