Creating the census dwelling frame for the 2023 Census describes the processes Stats NZ followed to develop a list of all known private and non-private dwellings (for example, communal or temporary accommodation) where people were on census night in New Zealand.
Contents
Summary
Strategic goals for creating the census dwelling frame
Creating the census dwelling frame
Summary
In the 2023 Census some households received their census material through the post while others received a visit from census field staff who delivered a census pack, which included an internet access code and paper forms.
The census operational frame provides the definitive list of physical addresses to mail census materials to, as well as the starting list for field staff visits.
The census operational frame drives the census collection ensuring we provide everyone in New Zealand with the means to complete the census. It is this operational frame, with field and response processing adjustments, that ultimately becomes the census dwelling frame.
The census dwelling frame is created from the census operational frame, after the census operational period and processing of census responses has concluded.
The census dwelling frame is the list of private and non-private dwellings in New Zealand for the 2023 Census.
Strategic goals for creating the census dwelling frame
The priorities and scope for the 2023 Census are set out in the 2023 Census: High Level Design.
2023 Census: High Level Design lays out strategic initiatives and scope statements for the 2023 Census as well as ways in which we responded to what we learned in the 2018 Census.
Creating the census dwelling frame relates to scope statements 33 and 42, which align to strategic initiative 2 of the high-level design:
- Strategic initiative 2: Deliver quality data to meet customer needs.
- Scope statement 33: A fit-for-purpose address list.
- Scope statement 42: Re-use of existing registers.
Creating the census dwelling frame
Statistical location register
The census operational frame was a selection of addresses extracted from the statistical location register (SLR). The SLR is a database of addresses maintained by Stats NZ for the purpose of the census and other surveys.
Addresses in the SLR are updated and maintained primarily by using administrative (admin) data sources from New Zealand Post and Land Information New Zealand, along with addresses from other Stats NZ surveys or observations (for example, previous census collections). From there, the categorisation of address types in the SLR was established by drawing insights from various sources.
Desktop canvassing
Desktop canvassing is a method of investigating, correcting, or verifying address data in the office, using online resources. This contrasts with field canvassing operations, which involve field staff walking streets and updating addresses through direct observation. Desktop canvassing was used in the lead-up to the 2023 Census to improve the quality of addresses and dwellings in the SLR and the census operational frame, particularly focusing on areas suitable for mailout.
Before Stats NZ created the census operational frame, a team of around 20 desktop canvassers worked to verify or correct address types that had some degree of uncertainty. These desktop canvassers used a range of tools to carry out these checks, including:
- Stats NZ’s internal mapping portal (known as the Geographic Data Explorer or GeoDex)
- New Zealand Post address and postcode finder
- Quotable Value property searches
- Stats NZ’s case management system (Salesforce)
- various council websites and property rating databases
- web-based mapping tools (for example, Google maps).
This work helped to ensure address types from the SLR were correctly identified and had the appropriate dwelling type. This brought addresses in and out of scope of the 2023 Census (for example, changing an address type from an empty section to a private dwelling).
Stream assignment and mode of delivery
The 2023 Census used a stream assignment methodology to determine the appropriate collection approach for dwellings in specific areas. The streams dictated how census materials would be delivered to the dwellings in allocated areas – either by mail or by field staff. The three streams for the 2023 Census were Assist, Deliver, and Mailout. These streams were allocated at the statistical area 1 (SA1) level (as opposed to the smaller meshblock level used in the 2018 Census). Nationally, 15 percent of dwellings were allocated to the Assist stream, 15 percent to the Deliver stream, and 70 percent to the Mailout stream.
The Assist stream was tailored to communities with historically lower census response rates, particularly in the 2018 Census, and featured demographics that are most poorly represented in official statistics. This included high-deprivation areas, populations with English as a second language, and areas with low internet connectivity. All dwellings in the Assist stream were delivered census packs by field staff.
The Deliver stream also involved delivery of census packs to addresses by field staff. It was assigned to SA1s (excluding those selected for the Assist stream) where census collection was expected to be complex (such as inner-city areas with high-rise apartments) or where there was lower confidence in the quality of the operational frame, or to areas with a high proportion of addresses that could not receive census packs through the default mailout process.
The count of addresses in the operational frame was compared with various comparative data sources, such as:
- final address counts from the 2018 Census plus building consents issued
- address counts from local council files
- counts of unique addresses identified in administrative data records.
SA1s in which the operational frame had consistently lower dwelling counts than comparative sources were added to the Deliver stream to allow field staff to identify and provide census packs to dwellings missing from the operational frame. Also included in the Deliver stream were SA1s that were anticipated to have higher counts of mobile dwellings and transient populations, and SA1s which New Zealand Post advised that less than 75 percent of dwellings could be mailed to.
All remaining dwellings were put into the Mailout stream and were sent census letters and packs through mail delivery. If New Zealand Post advised that a dwelling could not be mailed to, the dwelling was supplied with a census letter or pack either by courier or by field staff.
More information on the different modes of delivery and streams can be found in the Collection model for the 2023 Census.
Census operational frame
In October 2022, an address list was extracted from the SLR using a set of defined rules to create the census operational frame for the 2023 Census collection. It was loaded into Salesforce (Stats NZ’s customer relationship management system). Between October 2022 and February 2023 (the start of the census collection phase), work was done on the operational frame to improve its quality .
The census operational frame consisted of addresses of dwellings that:
- were to be mailed a letter that included an internet access code only (around 56 percent of dwellings)
- were mailed a census pack, which included paper forms and an internet access code (around 14 percent of dwellings)
- had a census pack, which included paper forms and an internet access code, delivered by field staff (around 30 percent of dwellings). Field staff could also add new dwellings and note any addresses they could not find. Office staff checked any changes.
Other address types (for example, commercial properties and empty sections with a building consent issued prior to November 2022) were included in areas where field staff visited dwellings. This enabled field staff to update the address types of any addresses needing census forms.
Some of the checks and updates that were done by office staff and field staff before, during, and after the collection period included:
- checking that the address string for dwellings was complete in order to meet New Zealand Post requirements
- removing duplicate addresses
- removing out-of-scope addresses
- ensuring any useful notes from the 2018 Census were included
- field staff adding new dwellings
- field staff changing address types
- staff from the public contact centre adding new dwellings in response to requests from the public for census forms, where their address was not in the census operational frame
- members of the address verification team checking changes and additions to the census operational frame made by field staff
- fixes made by the Address Verification and Response Reconciliation team.
Address canvassing
For the 2018 Census, a major field canvassing operation was undertaken as part of developing the new operational frame. With an established frame available for the 2023 Census, a more limited desktop canvassing process was implemented prior to the collection period.
The confidence in the quality of clusters of addresses (within SA1 areas) in the operational frame affected the mode of delivery, which led to address canvassing being part of the field operation. Areas with high growth, or a mixture of commercial and private dwellings, for example, were likely allocated to the Deliver stream, where field staff both checked and edited the list of addresses, and then left packs of forms at confirmed dwellings. While areas were selected for the Assist stream using different criteria, these were similarly canvassed in the field during the collection operation.
For non-private dwellings (for example, retirement villages and hospitals), work to improve the quality of the frame prior to operations included an in-house review of administrative-sourced lists (for example, public hospitals), combined with a field checking phase (November-December 2022).
Address verification and response reconciliation
The Address Verification and Response Reconciliation service (AVRR) provided desktop canvassing support from October 2022 through to the end of the collection period for the 2023 Census. This service included 55 technicians and five team leaders and expanded to approximately 90 staff during the collection period. The AVRR team reviewed over 850,000 unique records, around 35 percent of the census operational frame, between October 2022 and October 2023.
In addition to standard desktop canvassing functions, AVRR reviewed dwellings that were added to the frame by contact centre staff. AVRR also reviewed census response data connected with unexpected data states. Examples of unexpected data states include:
- responses where the given addresses did not match against an existing SLR address
- responses that were received from ‘non-dwellings’ like commercial buildings
- situations where multiple groups of responses were allocated to the same dwelling.
As a result of some of these checks the AVRR team added new addresses and dwellings to the operational frame and updated address types as needed. The AVRR team’s review also served as a quality check for the stock of canvassed dwellings, helping ensure respondents were being counted at their census night residence. The team also supported field staff efficiencies by reducing the number of unnecessary follow-up visits. The AVRR service used most of the same tools used in the desktop canvassing operation done prior to October 2022.
Census dwelling frame
The census dwelling frame is formed after the collection period for the census and after the processing of census forms. It includes identified private and non-private dwellings, along with dwellings under construction, and excludes any out-of-scope addresses (for example, commercial properties, empty sections, and addresses not found).
A number of issues were corrected after the 2023 Census collection finished, and before the census dwelling frame was created. The main corrections made were:
- removal of duplicate addresses
- identifying and correcting the classification of non-private dwellings and private dwellings within non-private dwelling situations (for example, rest homes)
- updating the coordinates of dwellings
- updating the occupancy status of dwellings.
Every dwelling on the census dwelling frame is allocated a variety of information (for example, occupancy status, meshblock, dwelling type and sub-type). This whole set of data is used as the basis of most census outputs and also feeds back into the SLR for future censuses and other statistical collections.
ISBN 978-1-99-104972-8 (online)
