National Family and Household Projections: 2001 (base) - 2021 Update

Alternative projection series

This release contains updated 2001-base family and household projections for New Zealand. These supersede the 2001-base national family and household projections released in June 2003. The projections have as a base the estimated resident population, estimated families and estimated households at 30 June 2001, and cover the period to 2021 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.

Nine alternative series have been produced from combinations of three population series and three variants of living arrangement type rates. For 2001–2004, the estimated resident population at 30 June is used for all national family and household projection series. For 2005–2021, series 1, 5 and 9 of the 2004-base national population projections released in December 2004 are used. Series 1 assumes low fertility, high mortality and low migration; series 5 assumes medium fertility, medium mortality and medium migration; series 9 assumes high fertility, low mortality and high migration.

The three variants of living arrangement type rates are:

1. Rates will remain constant at 2001 levels.
2. Rates will change linearly between 2001 and 2021 based on an assessment of observed trends between 1986 and 2001, and likely future trends, by sex and single-year of age.
3. Rates will change linearly between 2001 and 2021 according to observed trends between 1986 and 2001, 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, variants A and C are 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 nine 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 2001-base projections?

National family and household projections are updated every 2–3 years. These projections have been updated to incorporate the latest national population projections (released 16 December 2004). Compared with the previous national population projections (series 4, released on 24 October 2002), mid-range series 5 of the latest national population projections assumes:

1. Net migration of 104,000 in the five years to 30 June 2006, 38,000 in the five years to 30 June 2011, and 50,000 in each subsequent five-year period. By comparison, the previous national population projections assumed net migration of 100,000 in the five years to 30 June 2006 and 25,000 in each subsequent five-year period. An average net migration level of 10,000 rather than 5,000 a year in the long-term better reflects recent and likely future migration trends, with changes in immigration policy during the last 20 years being a key factor behind the increase in average annual net migration.
2. A slightly older net migration profile, with lower net inflow among the student ages (around 18 years).
3. A rise in the total fertility rate from 1.97 in 2001 to 2.01 in 2004–2005, then dropping to 2.00 in 2006, 1.92 in 2011 and 1.85 from 2016. By comparison, the previous national population projections assumed the total fertility rate dropped to 1.89 in 2006 and 1.85 from 2011.
4. Life expectancy at birth will increase to 80.7 years for males and 84.8 years for females in 2021. By comparison, the previous national population projections assumed life expectancy at birth of 80.3 years for males and 84.8 years for females in 2021.

The combined effect of these changes is that the New Zealand population is expected to reach 4.13 million in 2006, 4.29 million in 2011, 4.45 million in 2016 and 4.59 million in 2021 (series 5, 2004-base national population projections). By comparison, under series 4 of the 2001-base national population projections, the New Zealand population was expected to reach 4.11 million in 2006, 4.25 million in 2011, 4.38 million in 2016 and 4.51 million in 2021. Differences in the projected age-sex structure of the population will also cause differences in the number, size and type of families and households.

Living arrangement type rate variants 'A' and 'C' are unchanged from the June 2003 release. Small adjustments have been made to the variant 'B' rates to ensure that, under series 5B, there are similar numbers of male and female partners in couple without children families and in two-parent families. Assumptions of the average number of people per other multiperson household, the average number of families per family household, and the proportion of one- and two-parent families with dependent children, also remain unchanged from the previous 2001-base national family and household projections.

Families

Under series 5B, the number of families is projected to increase by 250,000 (24 percent) between 2001 and 2021, from 1.05 million to 1.30 million. Because of the changing age structure of the population, this will exceed the population growth of 18 percent 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 15,000 a year in 2002–2006 to 11,000 a year in 2017–2021. 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.

Series 9A, which assumes high fertility, low mortality, high migration and living arrangement type rates constant at 2001 levels, projects the highest number of families in 2021. Under this series, families would increase in number by 290,000 (28 percent) to 1.34 million in 2021. The smallest increase in the number of families is given by series 1C, with an increase of 160,000 (16 percent) to 1.22 million in 2021. This series assumes low fertility, high mortality, low migration and living arrangement type rates changing linearly between 2001 and 2021 based on the observed trend between 1986 and 2001.

 

Family type

Couple without children families will account for the majority of growth in the number of families. There are projected to be 215,000 (53 percent) more couple without children families in 2021 than in 2001, with an increase from 407,000 to 623,000. 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 after World War II reach ages 50 years and over. An increasing proportion of couples in (a) is also assumed to contribute to the increasing number of couple without children families, but to a lesser extent.

The number of one-parent families is projected to increase by 56,000 (28 percent), from 198,000 in 2001 to 254,000 in 2021. This 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 of 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 2001 level, series 5A shows that the number of one-parent families would increase by 29,000 (14 percent), to 227,000 in 2021. 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 after 2006, because of the continuing trends towards single parenting and fewer couples having children. Under series 5B, the number of two-parent families will increase from 446,000 in 2001 to 456,000 in 2006, but then fall to 427,000 by 2021. If living arrangement type rates were to remain at 2001 levels, series 5A projects a 10 percent increase in the number of two-parent families between 2001 and 2021, to 490,000.

Two-parent families were the most common family type in 2001, accounting for 42 percent of all families. Under series 5B, couple without children families are projected to surpass two-parent families as the most common family type by 2006. Couple without children families will account for 48 percent of all families by 2021, while two-parent families will account for 33 percent. Couple without children families accounted for 39 percent of all families in 2001. One-parent families are projected to account for 19 percent of all families throughout the projection period.

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 2001, about 84 percent of two-parent families and 77 percent of one-parent families contained dependent children. Assuming these proportions increase slightly during the projection period, the number of families with dependent children is projected to increase from 525,000 in 2001 to 561,000 in 2021. Growth will slow throughout the projection period, with an increase of 31,000 families with dependent children in the first ten years of the projection period (2002–2011), but an increase of only 4,000 in the last ten years of the projection period (2012–2021). The slowing growth mainly reflects the projected trends in the total number of two-parent families discussed in the previous section (Family type).

Within these families, the number of two-parent families with dependent children is projected to increase from 372,000 in 2001 to 382,000 in 2006, but then decrease to 363,000 by 2021. In contrast, the number of one-parent families with dependent children will increase throughout the projection period, from 153,000 in 2001 to 178,000 in 2011 and 198,000 in 2021. Two-parent families will account for 65 percent of families with dependent children in 2021, down from 71 percent in 2001.

Households

Under series 5B, the number of households is projected to increase by 400,000 (28 percent), from 1.44 million in 2001 to 1.84 million in 2021. This is faster growth than that of families (24 percent) and the population (18 percent) over this period, reflecting the trend towards smaller average household size and the increasing number of non-family households. A household is defined as one person usually living alone, or two or more people usually living together and sharing facilities (eg eating facilities, cooking facilities, bathroom and toilet facilities, a living area) in a private dwelling.

The number of households is projected to increase under all nine projection series. The largest increase is projected under series 9C, which assumes high fertility, low mortality, high migration and living arrangement type rates changing linearly between 2001 and 2021 based on the observed trend between 1986 and 2001. Under this series, the number of households will increase by 470,000 (33 percent) to 1.92 million in 2021. The smallest increase is projected under series 1B, which assumes low fertility, high mortality, low migration and living arrangement type rates changing linearly based on an assessment of trends between 1986 and 2001 and likely future trends. Under this series, the number of households will increase by 350,000 (24 percent) over the projection period, reaching 1.79 million by 2021.  

Household type

One-person households are projected to be the fastest-growing household type, increasing by 154,000 (46 percent) from 333,000 in 2001 to 488,000 in 2021. One-person households will account for 26 percent of all households in 2021, up from 23 percent in 2001. The growth in this household type will be mainly due to the increasing number of people at older ages, with 80 percent of the growth occurring among those aged 55 years and over. Of all people in one-person households, 64 percent are projected to be aged 55 years and over in 2021, compared with 57 percent in 2001.

Family households are projected to increase by 230,000 (23 percent), from 1.02 million in 2001 to 1.25 million in 2021. 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 2021 (68 percent) than in 2001 (71 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 1.03 families per family household in 2001.

The number of other multiperson households (households containing more than one person, but not containing a family) is expected to increase from 88,000 in 2001 to 102,000 in 2021. This is an increase of 13,000 or 15 percent. Other multiperson households will account for 6 percent of all households throughout the projection period. People aged 18–28 years will continue to account for about half of all people in other multiperson households.

 

Average family and household size

Household size distribution

Households containing one or two people are projected to account for nearly all of the growth in the number of households. Both one-person and two-person households are projected to increase in number by about 50 percent between 2001 and 2021. Over this period, the number of one-person households will increase from 333,000 to 488,000, while the number of two-person households will increase from 489,000 to 719,000. The growth in two-person households is mainly due to the increasing numbers of couple without children families and one-parent families, together with the decrease in the average size of one-parent families (ie more one-parent families will consist of a parent and only one child). Two-person households will account for 39 percent of all households in 2021, up from 34 percent in 2001. The share of households containing only one person will also increase, from 23 percent in 2001 to 26 percent in 2021.

Three-person households are projected to increase by 16,000 (7 percent) between 2001 and 2021. However, they will account for a smaller proportion of all households in 2021 (14 percent) than in 2001 (17 percent). The number of households containing four or more people is projected to increase between 2001 and 2006, but then slowly decline. In 2021, the number of households containing four or more people will be similar to the number in 2001. About 21 percent of households will contain four or more people by 2021, compared with 26 percent in 2001.

Living arrangement types

The updated 2001-base national family and household projections were produced by allocating people to one of eleven 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 partners in couple without children families. The number of people in this living arrangement type is projected to increase by 53 percent, from 810,000 in 2001 to 1.25 million in 2021. The main factor behind this growth is the increasing number of people in ages 50–90 years, where living in a couple without children family is the most common living arrangement type. Most couples in these ages will have had children who have left the parental home. In 2021, 72 percent of partners in couple without children families are projected to be aged 50 years and over, compared with 63 percent in 2001.

Population ageing is also the main reason for the large projected increases in the numbers of people in one-person households (ie living alone) and people living in non-private dwellings (which includes retirement homes), up 46 percent and 34 percent, respectively, between 2001 and 2021. Almost 11 percent of the population will be living alone in 2021, compared with 9 percent in 2001. The number of people aged 80 years and over living in a non-private dwelling is projected to almost double between 2001 and 2021, from 21,000 to 40,000. This is despite a small assumed decrease in the proportion of older people living in non-private dwellings, due to improvements in life expectancy and well-being in the older ages.

The number of parents in one-parent families is projected to increase by 28 percent between 2001 and 2021. This 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 average number of births per woman, the number of children in one-parent families will increase at a slower rate, up 16 percent between 2001 and 2021. An increase in the rate of single parenting and fewer couples having children will mean there are 4 percent fewer parents in two-parent families in 2021 than in 2001. The number of children in two-parent families will fall by 7 percent over the same period.