The variants give further information on the projected populations of Scottish council areas, and highlight the uncertainty around projecting future population, especially for small areas.
Detailed single year of age and sex projected populations are available for the previously published and the additional variant population projections:
- High migration variant
- Low migration variant
- High life expectancy variant
- Low life expectancy variant
- High fertility variant
- Low fertility variant
- Zero migration variant
Scroll charts make it easy to compare the projected population for different variants for each council area.
The difference between the high and low fertility variants and the principal projection is dependent on the proportion of women of childbearing age and the local fertility scaling factors. For areas with a low proportion of women of childbearing age, the fertility variant projected populations are relatively close to the principal projection. This is the case for Eilean Siar and the Orkney Islands. For areas where a larger proportion of the population falls into this category, the effect of the fertility variants is more significant, as is the case for West Dunbartonshire and West Lothian. However, for areas such as City of Edinburgh where the local fertility scaling factor is low (0.7) and the proportion of women of childbearing age is high due to the high student population, the effect of changing the fertility assumptions is small.
Changing life expectancy assumptions also has differing effects on the projected population for each area of Scotland. Areas which have a high proportion of older aged people and less migration tend to be more affected by the changes in life expectancy assumptions. For example, the life expectancy variant population projections for Eilean Siar and Dumfries & Galloway varies significantly from the principal projection for these areas.
The biggest variance from the principal projected population for almost all areas is for the high and low migration variants. The difference from the principal projection is dependent on the migration assumptions for the area.
For most council areas the projected populations for the variants followed a similar pattern to Scotland with the high migration variant projecting the highest population for 2033, then the high fertility, high life expectancy, the principal projection, and below this the low life expectancy, low fertility and then low migration variant. The zero migration variant gave the lowest projected population for Scotland compared with the other variants mentioned. The results for the zero migration variant differ significantly across the council areas depending on the migration assumptions for the principal projection. For example, for Inverclyde council area where the projected long-term net migration assumption is -400, the zero migration assumption leads to a higher projected population for 2033 than the principal projection. In contrast, for East Lothian where the projected long-term net migration assumption is +850, the zero migration assumption leads to a lower projected population for 2033 than the principal projection.