National Records of Scotland

Preserving the past, Recording the present, Informing the future

Annex B: Definitions, uses and limitations of the household projections

Annex B: Definitions, uses and limitations of the household projections

1. Definitions used in the household projections

The following definitions are used in this publication:

  • Household: The 2001 Census definition of a household is used - one person living alone, or a group of people (not necessarily related) living at the same address with common housekeeping (that is, sharing either a living room or sitting room or at least one meal a day). This excludes people living in communal establishments.

  • Private household population: The population living in private households, i.e. people not living in communal establishments.

  • Communal establishment:  An establishment providing managed residential accommodation, such as a hospital, care home, prison, student hall of residence or barracks. ‘Managed’ means full-time or part-time supervision of the accommodation.

  • Head of household: The head of the household is normally the first person entered on the Census form. The number of heads of household will be equal to the number of households. 

  • Children: Where children are included in a household type, they mainly consist of children aged 0-15, but they may also include a number of 16-18 year olds classified as dependent children in the Census (mainly people still at school). 

  • Average household size: The average number of people in private households is calculated by dividing the private household population by the number of households.

Figures in the tables are rounded to the nearest ten. Therefore, the totals shown may not be equal to the sum of the constituent parts.

2. Uses

The main use of the household projections is contributing to the assessment of future housing demand. Local authorities make widespread use of the household projections in development plans to assess future housing need, and as a context for planning decisions. The use of household projections for planning purposes is guided by central government policy and advice (Scottish Planning Policy 3: Planning for Housing (SPP 3) and Planning Advice Note 38: Housing Land (PAN 38)).  Projections are (or should be) only one element in assessing future housing need.

More information about the planning system in Scotland is available from the Scottish Executive website.

3. Limitations

These household projections have limitations. A projection is a calculation showing what happens if particular assumptions are made. The household projections are trend-based, and are not, therefore, policy-based forecasts of what the Government expects to happen. Many social and economic factors influence the formation of households, including policies adopted by both central and local government. Local planning policies are often intended to modify past trends. Development plans may be based on reasoned and agreed departures from the projections, that seem better able to fit particular local circumstances.

4. Population projections

The household projections are based on the population projections and, as a result, assumptions used for the population projections, such as future migration, fertility and mortality, will have an effect on the household projections. Since smaller areas tend to be affected more by migration, which is hard to predict, projections for these areas tend to be less reliable than those for areas with large populations, and the further into the future the projections are taken, the less reliable they are likely to be.

5. The use of Census-based trend in household formation patterns

The household projections use information on household type and age group from the 1991 and 2001 Censuses, projected forward to the end of the projection period. The headship rate is defined as the proportion of people in each age group and household type who are ‘head’ of a household.

For these projections, changes in household formation patterns between 1991 and 2001 – the most recent 10 year period - are projected forward to 2024. This method assumes that past trends in household formation will continue, but this may not necessarily be the case. The overall number of households is updated every year, but no information is incorporated on changes in household types between Censuses.

With the assistance of the Household Analysis Review Group, we are investigating ways to refine the household projections methodology.

6. Relationship to other projections

These projections apply a single methodology across all local authority areas. Individual authorities may have a wider range of local information – based for example on local population or household surveys – on which to compile local projections. The supporting material on the GROS website should assist in providing an understanding of the basis of our projections. We are happy to provide additional supporting or background material which users would find useful in assessing and using the projections.

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