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Projected Population of Scotland (2010-based)

2. Uses and limitations of projections

2.1. It is increasingly important to have high quality population statistics and also projections of the population, for both policy development and for planning and providing public services in different geographic areas.

2.2. The primary purpose of the national projections is to provide an estimate of the future population of Scotland as a common framework for use in national planning in a number of different fields such as education and health. Projections are used for teacher workforce models, and looking at the implications of an ageing population. They are also used for making national and international comparisons, benchmarking other projections, and as a control for smaller area projections.

2.3. But population projections have limitations. A projection is a calculation showing what happens if particular assumptions are made. The population projections are trend-based. They are, therefore, not policy-based forecasts of what the government expects to happen. Many social and economic factors influence population change, including policies adopted by both central and local government. The relationships between the various factors are complex and largely unknown.

2.4. The effect of the assumptions about future migration, fertility and mortality is often limited by the inertia in population change, the future population of an area is strongly influenced by the initial base population. As the process of change is cumulative, the reliability of projections decreases over time. Change affects some populations more rapidly and more seriously than others. Projections of the number of adults are usually more reliable than those for children because of difficulties in projecting levels of fertility and parental migration. The size of the migration flows, and the uncertainty of future trends, mean that for many areas the migration assumptions are more critical than the fertility and mortality assumptions.

2.5. Population projections, like some other types of projections, may indicate that existing trends and policies are likely to lead to outcomes which are judged undesirable. If new policies are then introduced, they may result in the original projections not being realised. However, this means the projections will have fulfilled one of their prime functions, to show the consequences of present demographic trends with sufficient notice for any necessary action to be taken.

2.6. It should be noted that as these population projections are trend based, they are less reliable in periods of rapid change. For example, the change in volume of migrants from the A8 accession countries to Scotland was not picked up by earlier projections.

2.7. The Scottish Government has set a target to match average European (EU15) population growth over the period from 2007 to 2017. More details can be found on the Scotland Performs website.

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