National Records of Scotland

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Comparison of 1996-based and 1994-based Household Projections

Comparison of 1996-based and 1994-based Household Projections

HSG/1998/5

Both the 1996-based and 1994-based household projections were produced using information on households from the 1971 and 1991 Censuses of Population data, together with the latest set of population projections.

1. Population projections

As stated previously, population projections produced by the National Records of Scotland provide one of the main inputs to the household projections. Changes between the 1994-based and 1996-based population projections have a direct impact on the 1996-based household projections compared to the 1994-based household projections.

The population projections are based on population estimates for the base year, and this base population is then projected forward using assumptions about births, deaths and migration. The 1996-based estimate was lower than had been projected by the 1994-based projections. This, together with some changes in the assumptions about fertility and migration, had the effects of lowering the projected population compared with the 1994-based projections

Chart 2

Chart 2  Comparison between 1994- and 1996-based population projections, Population aged 16  only

For household projections, the relevant population for the formation of households is the adult population aged 16 and over. As the chart above clearly shows, the 1996-based population projections produce fewer projected numbers of persons in the adult population than the 1994-based population projections.

On this basis, we would expect the 1996-based household projections to be lower than the 1994-based household projections.

2. Categories of household type

The categories of household type used for the 1996-based household projections are the same as those used for the 1994-based household projections, but differ from those used for the 1992-based projections. There were several reasons for the change in categories of household type and these are noted in Annex A.

As for the 1994-based projections, the current set of projections has household type defined in terms of the household composition (numbers of adults and children) and the age group of the head of household.

3. 1994-based household projections compared to 1996 household estimate

The 1994-based household projections overestimated the number of households for the projection year 1996 by approximately 12,500. The 1996-based household projections start with the baseline figure for 1996 which is the 1996 household estimate. As a result, the 1996-based household projections will be lower than the 1994-based household projections at that point.

As can be seen from the chart below, the 1996-based household projections are lower than the 1994-based projections throughout the projection period. There are around 16,500 fewer households projected for the year 2008 using the 1996-based household projections than were projected from the 1994-based projections.

Chart 3

Chart 3  Comparision between 1994- and 1996-based household projections

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