Definitions of key terms used throughout Facts, Stats and Figures

Age-Sex Structure:  A younger population typically has a higher proportion of younger people (the base of the pyramid) and a progressively smaller proportion of older people (the peak of the pyramid). An ageing population is typically represented by more of a rectangle shape, which has a bulge in the middle of the pyramid and a high proportion of older people at the top.

Area Unit: Non-administrative geographic areas created by Statistics New Zealand and roughly relate to suburbs. In Christchurch City there are 129 area units. View map(external link) [PDF 1.15MB]

Average Household Size: The mean number of people per household. It is calculated by dividing the number of people in households by the number of households. 

Avon Heathcote Eatuary /Ihutai Water Quality Index: In 2014 ECAN started using an index to rate water quality sites from Very Poor to Very Good based on teh Canadian Council of Ministers for the Environment(CCME) water quality index.  More information about this index can be founfd on page 6 of the Healthy Estuary and Rivers of Christchurch - Water quality of the Estuary of the Heathcote and Avon  Rivers / Ihutai report 2014(external link).

Brownfield Site: Area of previously developed land that is generally vacant or derelict. They are often former commercial or industrial sites which may or may not be contaminated.

Building Consents: May be for detached, semi-detached or attached dwellings and units. The majority of building consents that are issued are completed, however there is a small proportion of consents that are issued but not constructed.

CCC General Service Satisfaction Survey: For general activities that most or all residents in the city use, such as water supply, waste collection and road surfaces, a representative random sample of all city residents over the age of 15 is used to measure resident satisfaction.

Central City or Four Avenues: Incorporates the three area units (Cathedral Square, Hagley Park and Avon Loop) bounded by Deans Avenue, Harper/Bealey Avenues, Fitzgerald Avenue and Moorhouse Avenue.

Deprivation: The New Zealand Deprivation Index reflects aspects of social and material deprivation, based on a combination of the following census data: income, employment, qualifications, owned home, support, living space, transport and communication. The scale reflects a continuum from 'least deprivation' to 'most deprivation'. More information from the University of Otago(external link)

Dwelling Units: Refers to new dwellings that have been consented for, generally intended for one household. The consent may be classified as for a separate dwelling or for an attached unit (e.g. apartment, terraced housing, joined townhouse etc.).

Estimated Resident Population: The estimated resident population of an area in New Zealand at a given date after census night is derived by updating the census usually resident population count for: estimated net census undercount; the estimated number of residents temporarily overseas on census night; natural increase (births less deaths) between census night and the given date; net migration (arrivals less departures) between census night and the given date. More information from Statistics New Zealand(external link)

Ethnicity: Ethnicity is the ethnic group or groups that people identify with or feel they belong to. Ethnicity is a measure of cultural affiliation, as opposed to race, ancestry, nationality or citizenship. Ethnicity is self-perceived and people can belong to more than one ethnic group. More infomation from Statistics New Zealand(external link)

Family: Refers to a couple, with or without child(ren), or one parent with child(ren), usually living together in a household. Couple-without-children families include (a) couples who will never have children, (b) couples who will have children in the future, and (c) couples whose children have left the parental home.

Floorspace: New business floorspace refers to building consents issued for new buildings and additions to existing buildings, within specified business zones.

New Zealand General Social Survey: The New Zealand General Social Survey(external link) (NZGSS) provides information on the well-being of New Zealanders aged 15 years and over. It covers a wide range of social and economic outcomes and shows how people are faring. In particular the survey provides a view of how well-being outcomes are distributed across different groups within the New Zealand population.

Greater Christchurch: Refers to the urban area of Christchurch City and Lyttelton Harbour, as well as the 'commuter belt' communities in Selwyn and Waimakariri Districts. More information from the Urban Development Strategy(external link)

Greenfield Area or Site: Area of previously undeveloped land used for agriculture, landscape design, or left vacant, which has been identified as being suitable for development. Generally located on the outskirts of an urban area.

Household: Defined as one person usually living alone, or two or more people usually living together and sharing facilities (for example, eating facilities, cooking facilities, bathroom and toilet facilities, a living area), in a private dwelling.

Income: Total personal income received is the before-tax income of a person aged 15 years or over in the 12 months ended 31 March 2013. The information is collected as income bands rather than in actual dollars. Total personal income can be combined with other income information from the same family or household to provide a range of measures (e.g. total household income). More information from Statistics New Zealand(external link)

Infill site: Infill sites are located in existing residentially developed areas and may include sites where the existing building is demolished and replaced with more than one unit, or the existing site is subdivided or cross leased.

Inflation: The consumer's price index (CPI) provides information about changes to the prices of consumer items New Zealand households buy, and provides the most commonly used and recognised measure of inflation in New Zealand. More information from Statistics New Zealand(external link) and Reserve Bank of New Zealand's 'Inflation Calculator'(external link)

(external link)Inflation Adjusted Income: The data is adjusted to reflect incomes as they would have been in June 2006, to remove the effects of inflation and allow for comparisons over time. Income applies to the population aged 15 years and over.

Life Expectancy: A summary measure of the death and survival rates of the population. The average length of life of a newborn baby, assuming they experience the age-specific mortality rates of that year throughout their life.

Longitudinal Business Frame: The Business Frame has been designed by Statistics New Zealand(external link), to primarily provide current, point-in-time snapshots of business populations, as well as longitudinal business data that follows the same units over time, providing information about long term trends.

Mean annual low flow (MALF): This describes how low the flow gets in a typical year. The lowest flow for each year is averaged across recorded years to estimate the mean annual low flow. To avoid splitting a single drought event across years, a water year (July to June) is used instead of a calendar year (Jan-Dec). Definition from LAWA website(external link).

Median Age: Half the population is younger, and half older, than this age.

Median Income: Half earn more than, and half less, than this figure.

MELAA: Middle Eastern/Latern American/African

Meshblock: The smallest geographic unit created by Statistics New Zealand for statistical data collection and processing. They are generally the size of a street block in urban areas, and can be aggregated to form area unitsIn Christchurch City there are approximately 3500 meshblocks.

Metropolitan part of the city: The area of Christchurch City prior to the 2006 amalgamation with Banks Peninsula District.

Natural Increase: Births minus deaths. Negative values denote natural decrease.

Net Internal Migration: Internal migration refers to the movement of people into and out of Christchurch from other parts of New Zealand. Net internal migration (calculated as arrivals minus departures) is a component of population growth. More information from Statistics New Zealand(external link)

Net External Migration: External migration refers to the movement of people into and out of Christchurch City from overseas. Net external migration (calculated as arrivals minus departures) is a component of population growth. More information from Statistics New Zealand(external link)

Net Migration: Net migration is expressed as a positive or negative figure and is derived by subtracting departures from arrivals. A positive net migration figure occurs when more people arrive in Christchurch than depart. A negative net migration figure occurs when there are more departures from Christchurch than arrivals.

Net New Housing: Net new housing refers to gross new housing minus any demolitions/rebuilds (i.e. it excludes replacement housing where a demolition has occurred). It is an indicator of what is being added to the city’s housing stock rather than replaced. The gross figure of new housing units will contain a number or replacement housing units where demolitions have occurred.

Occupied Dwelling: For census use, a dwelling is defined as occupied if it is: occupied at midnight on the night of census data collection, or occupied at any time during the 12 hours following midnight on the night of census data collection unless the occupant(s) completed a questionnaire at another dwelling during this period. This includes occupied dilapidated dwellings and occupied dwellings under construction. More information from Statistics New Zealand(external link)

Occupied Non-Private Dwelling: Occupied non-private dwellings provide short or long-term communal or transitory type accommodation. They are generally available to the public for reasons of employment, study, special need, legal requirement, or recreation. They include: guest accommodation (e.g. hotels, youth hostels etc.), communal living (e.g. camps, hospitals, institutional complexes etc) and facilities for paying guests (e.g. home stays, farm stays etc.). More information from Statistics New Zealand(external link)

Occupied Private Dwelling: An occupied private dwelling accommodates a person or group of people and is not generally available for public use. The main purpose of a private dwelling is as a place of habitation; it is usually built (or converted) to function as a self-contained housing unit. More information from Statistics New Zealand(external link)

Population Density: The number of usual residents in a standardised area (per square hectare), and reflects the concentration of population. Density is influenced by land zoning, housing type and household composition. More information from Statistics New Zealand(external link)

Population, Household and Family Projections: Statistics New Zealand produces projections based on assumptions about future fertility, mortality and migration. Three projections (low, medium, and high growth) incorporating different fertility, mortality, and migration assumptions for each geographic area have been produced to illustrate a range of possible scenarios. At the time of release, Statistics NZ considers the medium projection suitable for assessing future population, family and household changes. Projections are not predictions. The projections should be used as an indication of the overall trend, rather than as exact forecasts. More information from Statistics New Zealand(external link)

Potential Sections: This is the total number of sections that the particular development is likely to yield once the whole development of the area is complete. The availability type can be further defined by:
- Sections with subdivision consent (number of sections within a development for which the Council has granted subdivision consent- may only apply to part of a development);
- Sections sold with subdivision consent (this information comes from the developer or their agent, and reflects the sales they have made);
- Sections for sale with subdivision consent (assumes sections are for sale as soon as they have received subdivision consent from the Council); 
- Sections with titles (number of sections with subdivision consent which have also been issued a Title by Land and Information New Zealand).

(external link)Qualification: A qualification is a formally recognised award for educational or training attainment, where formal recognition means that the qualification is approved by a specified authority. More information from Statistics New Zealand(external link) 

Quantitative Macroinvertebrate Community Index (QMCI): The QMCI is a set of biotic indices used to monitor and report on the health of New Zealand streams.  These indices were created by the Ministry for the Environment and are used by the Christchurch City Council, in conjunction with Environment Canterbury and Avon-Heathcote Estuary Ihutari Trust.  More information from the Ministry for the Environment(external link)

Residential Red Zone: Post-earthquakes, areas in the flat land residential red zone which have area-wide land and infrastructure damage, and an engineering solution to repair the land would be uncertain, costly, and is likely to be highly disruptive. Areas in the Port Hills which are affected by cliff collapse and/or rock fall where there is unacceptable risk to life and cannot be easily remediated or mitigated. More information from CERA(external link)

Rezoning: This reflects is where zoning is changed in the Christchurch District Plan(external link) through a formal process.

Sources of Income: Identifies the various sources from which an individual aged 15 years and over received income in the 12 months ending 5 March 2013. More information from Statistics New Zealand(external link)

Study Participation: Measures those attending, studying, or enrolled at school or anywhere else. It is grouped into full-time study (20 hours or more a week), part-time study (less than 20 hours a week), and those not studying. More information from Statistics New Zealand(external link)

Surrounding Districts: Refers to Waimakariri and Selwyn Districts.

Trophic Level Indicator (TLI): The higher TLI scores mean poorer water quality, due to higher nutrients and fertility of the water which encourages growth, including algal blooms. Four parameters are measured: water clarity, chlorophyll content, total phosphorus and total nitrogen. From these parameters a TLI value is calculated. In cases where water clarity data is missing a three parameter TLI is calculated.   View a factsheet on TLI(external link) one the LAWA website.

UK (Not further defined): This category captures migrants who specified 'United Kindgom' on their arrivals card as the country of last residence, without specifying which country (e.g. England, Wales, Scotland or Northern Ireland- which each have their own category).

Unoccupied Private Dwelling: For census use a private dwelling (i.e. place of habitation not generally available for private use) is defined as unoccupied if it is unoccupied at midnight and at all times during the next 12 hours following midnight on the night of the data collection. Unoccupied dwellings may be classified as 'empty' or 'residents away'. More information from Statistics New Zealand(external link)

Vacant Industrial land: Defined in the City Plan as undeveloped areas on which potential future development is allowed. The area of vacant industrial land available and its take up are measures from which policy makers and planners can determine if there is sufficient land available for industrial development. Industrial land is classified as vacant if no industrial buildings are present or partially vacant if sufficient land remains to construct additional industrial buildings. Industrial Zones are a subset of Business Zones, plus some Special Purpose Zones. Industrial Zones do not include Business Centre or Business Retail Park Zones. Vacant industrial land does not necessarily consist of bare paddocks. It may already be in use as an industrial yard or truck park, as a storage area for piles of industrial material, or may contain residential buildings that pre-date the creation of an industrial zone.

Vacant Residential Land: Defined in the District Plan as undeveloped areas on which potential future development is allowed. It is classified as:
- Subdivided/Redeveloped (these are smaller lots of vacant land with access and which are ready to be built on);
- Undeveloped (large parcels of land which are completely vacant, or, land parcels larger than one hectare with an existing dwelling);
- Potential (land parcels between 0.4 and 1 hectares in size that have a single existing dwelling, but could be subdivided at the discretion of the owner, subject to applicable zoning rules);
- Deferred Zoning, land which is currently subject to deferred zoning decisions, i.e. land that is earmarked for future growth but is deferred to allow for strategic timing around market supply and infrastructure provision.