Background
This release contains updated 2006-base family and household projections for New Zealand. These supersede the 2006-base national family and household projections released in December 2008. The projections have as a base the estimated resident population, estimated families, and estimated households at 30 June 2006, and cover the period to 2031 at one-year intervals. These projections are neither predictions nor forecasts. They provide an indication of possible future changes in the number and composition of families and households.
A family, as defined here, consists of a couple, with or without child(ren), or one parent with child(ren), usually living together in a household. Couples include opposite-sex and same-sex couples. A household is 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.
Detailed projection results, with projections for individual years are freely available from Infoshare on the Statistics NZ website (www.stats.govt.nz), or on request email demography@stats.govt.nz. Updated subnational family and household projections for regional council and territorial authority areas will be released on 13 December 2010.
Alternative projection series
Six alternative series have been produced from combinations of three population series (series 1, 5, and 9) and two variants of living arrangement type rates (A and B). Series 1, 5, and 9 of the 2009-base national population projections released in October 2009 are used. Series 1 assumes low fertility, high mortality, and low migration; series 5 assumes medium fertility, medium mortality, and medium migration; and series 9 assumes high fertility, low mortality, and high migration.
The two variants of living arrangement type rates are:
A. Rates will remain constant at 2006 levels.
B. Rates will change linearly between 2006 and 2031, based on an assessment of observed trends between 1986 and 2006 and likely future trends, by sex and single-year of age.
Variant B is the preferred variant, because it has been formulated to produce demographically plausible results by assessing both historical trends and likely future trends. For comparison, variant A is formulated solely on the basis of historical rates.
Each family and household projection series is denoted by the population projection series and variant of living arrangement type rates. For example, series 5B denotes that variant 'B' living arrangement type rates have been applied to population projection series 5. Further details of the assumptions are contained in the Technical notes.
Which projection series should I use?
The six alternative series have been produced to illustrate a range of possible scenarios. Users can make their own judgement as to which projection series is/are most suitable for their purposes. However, at the time of release, Statistics New Zealand considers projection series 5B the most suitable for assessing future family and household changes. The following analysis is based on series 5B unless otherwise stated.
What has changed from the previous 2006-base projections?
National family and household projections are updated every 2–3 years. These national family and household projections have been updated to incorporate the latest demographic information, notably the 2009-base national population projections (released 27 October 2009).
Compared with the previous 2006-base national population projections (released 24 October 2007), mid-range series 5 of the 2009-base projections assumes higher fertility, higher mortality, and higher net migration in the short term. The projection assumptions for the national family and household projections incorporate these changes. The combined effect of these changes, with updated living arrangement type rates, is that under series 5B there will be 1.46 million families in 2031 (from the updated 2006-base projections) compared with 1.44 million families in the previous 2006-base projections. The number of households remains similar, at 2.09 million in 2031 under series 5B.
Families
Under series 5B, the number of families is projected to increase by 288,000 (an average of 0.9 percent a year) between 2006 and 2031, from 1.17 million to 1.46 million. Because of the changing age structure of the population, this will exceed the population growth, which will average 0.8 percent a year over the same period. Like population growth, growth in the number of families is expected to slow over the projection period – from an average of 14,000 a year in 2007–11 to 9,000 a year in 2027–31.
Series 9A, which assumes high fertility, low mortality, high migration, and living arrangement type rates constant at 2006 levels, projects the highest number of families in 2031, with an increase of 358,000 (an average of 1.1 percent a year) to 1.53 million in 2031. The smallest increase in the number of families is given by series 1B, with an increase of 237,000 (an average of 0.7 percent a year) to 1.40 million in 2031. This series assumes low fertility, high mortality, low migration, and living arrangement type rates changing linearly between 2006 and 2031, based on the observed trends between 1986 and 2006 and likely future trends.
Family type
Couple-without-children families will account for the majority of growth in the number of families. There are projected to be 253,000 more couple-without-children families in 2031 than in 2006, increasing from 468,000 to 721,000 (at an average of 1.7 percent a year). 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. Growth in (c) is expected to be the most significant, as the large number of people born during the 1950s to early 1970s reach the older ages. An increasing proportion of couples in (a) is also assumed to contribute to the growing number of couple-without-children families, but to a lesser extent.
The number of one-parent families is projected to increase by 48,000 (an average of 0.8 percent a year), from 219,000 in 2006 to 267,000 in 2031. This increase is because of population growth, changes in population age structure, and an assumed higher rate of single parenting. The latter is due to increasing numbers of separations and divorces, increasing rates of childbearing outside couple relationships, and more complex shared-care arrangements with parents residing in different households. If the rate of single parenting was to remain at the 2006 level, series 5A (which assumes medium fertility, medium mortality, high migration, and living arrangement type rates constant at 2006 levels) shows that the number of one-parent families would increase by 41,000 (an average of 0.7 percent a year), to 260,000 in 2031. It should be noted that children in families can be of any age, and can include a mature child living with older parent(s).
The number of two-parent families is projected to decrease because of the continuing trends towards single parenting and fewer couples having children. Under series 5B, the number of two-parent families is projected to decrease from 481,000 in 2006 to 468,000 by 2031. If living arrangement type rates were to remain at 2006 levels, series 5A projects an increase in the number of two-parent families between 2006 and 2031, to 540,000.
Two-parent families were the most common family type in 2006, accounting for 41 percent of all families. Couple-without-children families accounted for 40 percent of all families in 2006. Under series 5B, couple-without-children families are projected to have surpassed two-parent families as the most common family type in 2008. Couple-without-children families will account for 50 percent of all families by 2031, while two-parent families will account for 32 percent. Despite increasing in number, one-parent families are projected to account for 18 percent of all families in 2031, down from 19 percent in 2006.
Families with dependent children
As children can be of any age, it is useful to distinguish families with dependent children (people aged under 18 years and not in full-time employment) from families with older children. In 2006, about 83 percent of two-parent families and 75 percent of one-parent families contained dependent children. Assuming these proportions remain constant during the projection period, the number of families with dependent children is projected to increase from 565,000 in 2006 to 591,000 in 2031.
Within these families, the number of two-parent families with dependent children is projected to decrease from 400,000 in 2006 to 389,000 by 2031. In contrast, the number of one-parent families with dependent children will increase throughout the projection period, from 165,000 in 2006 to 201,000 in 2031. Two-parent families will account for 66 percent of families with dependent children in 2031, down from 71 percent in 2006.
Households
Under series 5B, the number of households is projected to increase by 536,000 (an average of 1.2 percent a year), from 1.55 million in 2006 to 2.09 million in 2031. This growth is faster than that of families (an average of 0.9 percent a year) and the population (an average of 0.8 percent a year) over this period, reflecting the trend towards smaller average household size and the increasing number of non-family households.
The number of households is projected to increase under all six projection series. The largest increase is projected under series 9B, where the number of households will increase by 612,000 (an average of 1.3 percent a year) to 2.16 million in 2031. This series assumes high fertility, low mortality, high migration, and living arrangement type rates changing linearly between 2006 and 2031, based on an assessment of observed trends between 1986 and 2006 and likely future trends. The smallest increase is projected under series 1A, which assumes low fertility, high mortality, low migration, and living arrangement type rates constant at 2006 levels. Under this series, the number of households will increase by 434,000 (an average of 1.0 percent a year) over the projection period, reaching 1.99 million by 2031.
Household type
One-person households are projected to be the fastest-growing household type, of the three broad types projected, increasing by 240,000 (an average of 2.0 percent a year) from 363,000 in 2006 to 602,000 in 2031. One-person households will account for 29 percent of all households in 2031, up from 23 percent in 2006. The growth in this household type will be mainly due to the increasing number of people at older ages, with almost three-quarters of the growth occurring among those aged 55 years and over. Of all people in one-person households, 68 percent are projected to be aged 55 years and over in 2031, compared with 59 percent in 2006.
Family households are projected to increase by 277,000 (an average of 0.9 percent a year), from 1.12 million in 2006 to 1.40 million in 2031. However, because of the faster increase in the number of one-person households, family households will account for a smaller share of all households in 2031 (67 percent) than in 2006 (72 percent). Family households can contain more than one family, or other people living with (but not in) a family. It is estimated that there was an average of 1.04 families per family household in 2006.
The number of other multi-person households (households containing more than one person, but not containing a family) is expected to increase from 68,000 in 2006 to 88,000 in 2031 – an increase of 20,000 or an average of 1.0 percent a year. Other multi-person households will account for 4 percent of all households throughout the projection period. People aged 19–29 years will continue to account for about half of all people in other multi-person households.
Average family and household size
The average size of households is projected to slowly decline between 2006 and 2031, from 2.6 to 2.4 people per household. This continues the decline seen in recent decades, with the average household size falling from 3.7 people in 1951 and 3.0 people in 1981.
The projected decrease in average household size is due to the increasing proportion of one-person households and a decrease in the average size of family households. The latter is projected to fall from 3.2 people in 2006 to 3.0 people in 2031, reflecting changes in both the type and size of families. By 2031, there are expected to be more couple-without-children families and one-parent families, but fewer two-parent families. Two-parent families are generally larger, with an average size of just under 4.0 people in 2006 and increasing slightly to just over 4.0 people by 2031. Couple-without-children families, by definition, contain two people. One-parent families contained an average of 2.6 people in 2006, reducing slightly to 2.5 people in 2031.
Living arrangement types
The updated 2006-base national family and household projections were produced by allocating people to one of 11 living arrangement types. Assumptions have been made about the future propensity of people to live in each living arrangement type, by age and sex. The projected number of families and households are derived from the projected population by living arrangement type.
Under series 5B, the living arrangement type projected to experience the fastest growth is one-person households. The number of people in this living arrangement type is projected to increase by an average of 2.0 percent a year from 363,000 in 2006 to 602,000 in 2031. The main reason for this growth is the movement of the large number of people born during the 1950s to early 1970s into the older ages. Twelve percent of the population will be living alone in 2031, compared with 9 percent in 2006.
Population ageing also contributes to the projected large increases in the numbers of people living in non-private dwellings (which include retirement homes), up an average of 1.4 percent a year between 2006 and 2031. The number of people aged 80 years and over living in a non-private dwelling is projected to almost double between 2006 and 2031, from 23,000 to 43,000. This increase is despite a small assumed decrease in the proportion of older people living in non-private dwellings, due to assumed increases in life expectancy and well-being in the older ages.
The number of parents in one-parent families is projected to increase by an average of 0.8 percent a year between 2006 and 2031. This increase is due to population growth, changes in population age structure, and a continuing increase in the rate of single parenting. However, because of a decline in the assumed average number of births per woman, the number of children in one-parent families will increase at a slower rate, up an average of 0.6 percent a year between 2006 and 2031. An increase in the rate of single parenting and fewer couples having children will mean there will be 3 percent fewer parents in two-parent families in 2031 than in 2006. The number of children in two-parent families in 2031 (956,000) will be similar to that in 2006 (954,000).
For technical information contact:
Kim Dunstan or Rino Adair
Christchurch 03 964 8700
Email: demography@stats.govt.nz