Uses
Household projections are mainly used for informing decisions about future housing need and service provision, and are used in the production of Development Plans.
Interpreting the projections
These household projections have limitations. A projection is a calculation showing what happens if particular assumptions are made. The household projections are based on population projections and, as a result, assumptions used for the population projections (particularly future migration, fertility and mortality) will have an effect on the household projections. Projections for small groups are likely to be less reliable than those for larger groups.
Every two years the Office of National Statistics (ONS), in consultation with the Registrars General, produces a "principal" population projection and a number of "variant" projections, based on alternative assumptions of future fertility, mortality and migration, for the UK and its constituent countries. These projections for National Park and SDP areas are based on the "principal" population projection.
The household projections are trend-based, rather than policy-based forecasts. They do not take into account social and economic factors that may influence the formation of households, including policies adopted by both central and local government as well as any imbalances between housing supply and demand.
Summary of the methodology
Household projections are based on the population projections produced by the General Register Office for Scotland. The number of people living in private households is estimated by taking the population projections for each year and subtracting the number of people living in communal establishments, such as student halls of residence, care homes or prisons. To estimate the number of households of each type, information on household type and age group is projected forward from the 1991 and 2001 Censuses, for each household type, age group and projection area. This information is applied to the private household population to produce the basic household projections.
A more detailed description of household projections methodology can be found at http://www.nrscotland.gov.uk/files/statistics/household-projections/2008-projections/j1180906.htm
Household projections for National Parks are based on the population projections for National Parks and are built up from the General Register Office for Scotland’s mid-2008 data zone populations. The overall projections for Scotland are believed to be more accurate than those for individual areas and therefore the National Park figures and the rest of Scotland are constrained to the Scottish total.
For SDP areas, household projections were calculated by aggregating the projections for the constituent council areas (which have already been published) and then subtracting any areas which do not form part of the SDP area such as areas which overlap with the National Parks. (For further details of the boundaries used, see Section 4)
Household types and age groups used in the household projections
National Parks
Household projections are produced for each National Park area, broken down into five household types (based on the number of adults and children living in the household) and three age groups. Due to small numbers it is not appropriate to produce projections for smaller age groups. Household types and age groups are shown here:
Household types |
|---|
1 person households: |
1 adult: male |
1 adult: female |
2+ person households: |
2+ adults |
1 adult, 1+ children |
2+ adults, 1+ children |
Age group of head of household |
|---|
16-34 |
SDP areas
Household projections are produced for each SDP area, broken down into seven household types (based on the number of adults and children living in the household) and 16 age groups, as follows:
Household types |
|---|
1 person households: |
1 adult: male |
1 adult: female |
2 person households: |
2 adults |
1 adult, 1 child |
3+ person households: |
1 adult, 2+ children |
2+ adults, 1+ children |
3+ adults |
Age group of head of household |
|---|
16-19 |