National Records of Scotland

Preserving the past, Recording the present, Informing the future

The base population and assumptions used in the projection

The base population and assumptions used in the projection

1. The base population: The projection is based on the Registrar General's population estimates for mid-2004. The population covered includes all persons usually resident in Scotland whatever their nationality. Members of HM and non-UK armed forces stationed in Scotland are included; HM forces stationed outside Scotland are excluded. Students are treated as being resident at their term-time address.

2. Fertility: The fertility rates used in the projection are based on assumptions about the average completed family size of successive cohorts of women. It has been assumed that the average completed family size will continue to decline from around 1.90 children per woman for those born in the late 1950s and now reaching the end of their childbearing lives, before levelling off at 1.60 for those born in the 1990s and later. A downward trend in the number of births is expected, to a projected level of about 46,000 by 2031. More details on the fertility assumptions are available in Annex A.

3. Mortality: Future improvements in mortality rates are based on the trend observed in the period 1961 to 2003.  It is assumed that annual rates of reduction in mortality rates will tend towards a common reduction at each age of 1 percent a year by 2029. Thereafter the mortality improvement is assumed to continue at this rate (in contrast to the previous projections where it was assumed to half every subsequent twenty-five years). In line with the long-term trends, it has been assumed that the mortality rates for Scotland will continue to be higher at most ages than those for England & Wales. Based on these rates, expectations of life at birth are projected to increase from 73.8 in 2002-04 to 79.1 in 2030-31 for males; and from 79.1 in 2002-04 to 83.6 in 2030-31 for females as shown in Figure 5. More details on the mortality assumptions are available in Annex B.

4. Migration: It is assumed that from 2008 onwards there will be a net inflow of 4,000 people per year to the end of the projection period, i.e. the total migration inflow is assumed to be greater than the total outflow. This assumption has been derived from analyses of trends in civilian migration to and from the United Kingdom as well as cross-border migration between the four constituent countries. In the first three years of the projection higher net inflows are assumed, reflecting recent trends as described in section 2.5. See Annex C for more details on the migration assumptions.

All statistical publications