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

The base population:

The projection is based on the Registrar General's Mid-2002 Population Estimates. The population includes everyone usually resident in Scotland, of whatever 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.

Fertility:

The fertility rates used in the projection are based on assumptions about the average completed family size of successive generations of women. It has been assumed that the average completed family size will continue to decline from just under 2 children per woman for those born in the mid to late 1950s and now reaching the end of their childbearing lives, before levelling off at 1.60 for those born in 1975 and later. The recent downward trend in the number of births is expected to continue for the projection period, falling below 50,000 in 2005 before declining further to a projected level of about 46,000 in 2027.

Mortality:

The mortality rates for the projections are based on long-term trends up to 2002. Generally, mortality rates are projected to fall, initially at varying rates but tending to a reduction of 1.0 per cent a year at all ages by 2027. 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 73.5 in 2002-03 to 78.4 in 2026-27 for males; and from 79.0 in 2002-03 to 83.2 in 2026-27 for females.

Migration:

The total outflow is expected to be slightly greater than the total inflow. A net out-migration of 1,500 each year is assumed from 2003-04 to the end of the projection period. These assumptions have 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. The loss in the first year of the projection period is assumed to be higher.

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