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Background to census processes and procedures

This chapter answers some common questions about the collection and processing of census data. For more information see Introduction to the New Zealand Census

What areas are covered by the census?

The geographic coverage of the census includes the North Island, South Island, Stewart Island, and the Chatham Islands, plus offshore islands including the Kermadec Islands, Three Kings Islands, Mayor Island, Motiti Island, White Island, Moutohora Island, Bounty Islands, Snares Islands, Antipodes Islands, Auckland Islands, and Campbell Island.

Counts of people by sex on Ross Dependency are taken but are not included in the New Zealand population count.

How is everyone counted in the census?

Producing high-quality data from the census starts with an efficient and successful collection process. The collection phase is a large logistical exercise that involves detailed planning, identifying and getting access to dwellings, locating respondents, and making sure respondents complete the census. There are three main elements to successful data collection:

  • delivery of census forms and an Internet access code for completion online to every person and occupied dwelling in New Zealand by census night
  • high response rate from those present in New Zealand on census night
  • efficient collection of census forms from every person and occupied dwelling that has not completed forms online.

Statistics New Zealand recruits a team of census collectors before each census. Each collector works an area, delivering and collecting census forms to individuals and households across New Zealand. They are fully trained and supported.

The collectors leave two types of forms: a dwelling form, and an individual form for everyone who will be in the dwelling on census night. Each dwelling is provided with an Internet access code so that people can fill in the census online if they choose to. Doing the forms online is secure, quick, and easy. If everyone in a household completes their forms online, a collector may not need to call back.

Collectors make every effort to deliver census forms to all dwellings. In addition to private dwellings, collectors deliver census forms to non-private dwellings, such as hotels, motels, prisons, hospitals, camping grounds, and even cruise ships.

It can be hard to find people at home in inner-city apartments, especially in Auckland and Wellington. Collectors use strategies for apartments including identifying high-rise inner-city apartments in advance, networking with building managers to access the apartments, and using extra resources to increase awareness among residents of these apartments. It is important to make the effort to reach people in apartments, as this can have significant impacts on data quality, particularly at the area unit or meshblock levels.

People can complete census forms in English or Māori using an English form or a Māori/English form. Collectors deliver the Māori/English form to all dwellings in Northland, Whakatane, Gisborne, and the Chatham Islands. In other areas, individuals can request a Māori/English form in three ways: from the collector, by ringing the toll-free census number, or through the census website.

To help individuals fill in census forms, we:

  • provide guide notes with the print and Internet census form to help respondents answer specific questions in the form, as well as questions that individuals may have while filling in the form
  • set up a toll-free census helpline number well before the census date, and offer this service in eight languages: English, Māori, Samoan, Tongan, Mandarin, Cantonese, Korean, and Hindi
  • offer online help through the census website.

Collection of paper census forms starts immediately after census day. Collectors return to dwellings to pick up the forms, unless everyone in a dwelling has filled in their forms online. After three attempts to contact dwelling occupants, the collector leaves a freepost envelope for the occupants to return forms.

Collectors will check (while collecting forms) that individuals have answered the key questions (foremost variables) on the first page of the individual form. This is a small but significant part of our quality management plan.

Who must fill in a census form?

Everyone in New Zealand on census night is required to complete a census form, under the Statistics Act 1975.

We recognise that the legal requirement is not itself enough to achieve the high response rate desired. We encourage people to participate in the census through a broad public communications programme – using advertising, news media, community programmes, and social media websites. The programme aims to tell people why the census is important, when it is, and how to take part. We can prosecute individuals who do not participate in the census or provide false information.

How is an individual's privacy protected?

We use several methods to protect the privacy and confidentiality of individuals who fill in census forms. These are in place from the time collectors deliver census forms through to the publication of census data.

2013 Census definitions and forms has more information on what happens to your census forms and how we maintain an individual’s privacy and confidentiality during the collection, transportation, processing, and storage of census forms.

Under the provisions of the Statistics Act 1975, we must ensure that any statistical information published does not identify any particulars about any individual or entity. To comply with this, we confidentialise the data, balancing the need to protect the details of individuals while providing useful information to users. We usually review confidentiality rules after each census and update them when necessary.

2013 Census confidentiality rules and how they are applied has the most recent information.

How do we know how many people were missed?

We undertake a Post-enumeration Survey (PES) after each census (since 1996). This estimates how many people were missed or counted more than once in the census.

The 2006 PES showed a net undercount of New Zealand residents in the country on census night of about 2 percent, which means the 2006 Census counted 98 percent of all New Zealand residents in the country on census night, compared with 97.8 percent for the 2001 Census.

Recent census coverage results in New Zealand are similar to those in Australia and Canada. For example, in Australia, 97.3 percent of people were counted in the 2006 census and 98.2 percent in 2001 (Census of Population and Housing – Details of Undercount – Australian Bureau of Statistics, 2011).

Results from the PES are used to adjust the population base for deriving post-censal population estimates and demographic projections. However, census counts are not altered.

The results of the 2013 PES are available in 2014.

How do topics get included in the census?

Census information covers a wide variety of topics, spanning many different areas, for example, income, education, work, housing, and culture and identity. Statutory requirements ensure certain information must be collected in each census:

  • the name and address, sex, age, and ethnic origin of every occupant of the dwelling
  • particulars of the dwelling – location, number of rooms, ownership, and number of occupants on census night (Statistics Act,1975).

Comparability of census information over time is one of its greatest strengths. Any change to census content reduces the ability of users to make these valuable comparisons and must be carefully considered.

New topics are added and existing questions changed to reflect real-world changes and emerging information needs. When including topics in the census, we are guided by these criteria:

  • Is the census the most appropriate information source?
  • Is there public acceptance of the topic?
  • Will the topic produce quality information?
  • Does the topic have significant community value?

There are constraints on what can and cannot be included. These are:

  • some topics are required by law
  • the collection of data must be cost effective
  • the length of the forms is limited
  • respondent burden and resistance must be minimised
  • continuity and relevance need to be balanced
  • the need for data consistency must be considered.

We invite submissions from the public and special interest groups and also consult users when considering changes to census content.

Following content decisions, the form-development phase involves redesigning the census forms, and balancing the requirements of content, printing, scanning, and the size of the forms.

The questions identified for redevelopment are usually those affected by data quality concerns from previous censuses (for example, growing numbers of people not answering the question or real-world changes that require revisions to questions to reflect new legislation or changes in terminology.

For more details on the content and form design phases of the 2013 Census, see:

(Please note that the 2011 Census was cancelled after the Canterbury earthquake on 22 February 2011, but the content and form design was used for the 2013 Census.) 

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