Projections overview

National family and household projections

Information releases | New Zealand Family and Household projections report

Projections of the numbers of families and households in New Zealand were derived from the 2009-base National Population Projections (released 27 October 2009) by multiplying the projected population by assumed living arrangement type rates for each age-sex group. The living arrangement type rates vary by age and sex, and are assumed to change over time with changes in social patterns (for example, age of cohabitation and marriage, fertility rates, rates of marriage dissolution, propensity and ability of people to live alone).

The projections of population by living arrangement type are subsequently aggregated to give projections of families (by broad family type) and households (by broad household type). The projections cover the period 2007–31 at one-year intervals.

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). Projection series 5B presented here assumes that:

  • New Zealand women will have 1.90 children each on average in the long-term
  • life expectancy at birth will increase to 82.1 years for males and 85.3 years for females in 2031
  • there will be a net migration gain of 25,000 in the June year 2010, 19,000 in 2011, and 14,000 in 2012 and 10,000 in each subsequent year
  • living arrangement type rates will change linearly between 2006 and 2031, based on assessment of observed trends between 1986 and 2006, and likely future trends, by sex and single-year of age.

Under this scenario, 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. Over the same period, 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.

A family is defined as 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, in a private dwelling.

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.

The number of two-parent families is projected to decrease because of the continuing trends towards single parenting and fewer couples having children. The number of two-parent families is projected to decrease from 481,000 in 2006 to 468,000 by 2031.

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. 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. 

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.

The number of households is projected to increase under all six projection series. 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.

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. 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.

Because of the increasing number of smaller households, 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.

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.