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Background to the population projection and limitations on its use

Statistics Finland's population projections should not be interpreted as descriptions of the inevitable. They are based on observations on past development in fertility, mortality and migration. The projections do not seek to estimate the effect of economic, socio-political regional policy and other such factors on population development. Thus, the calculations mainly indicate the outcome from the present development under the assumption that it continues unchanged.

"There are numerous examples of how the development of population in municipalities has been influenced even in short-term by regional and social policy or economic factors. Indeed, a population projection is first and foremost a tool with which decision-makers can assess whether the present development is desirable or whether corrective measures need to be taken. The task of a projection is to alert decision-makers to taking action as necessary," says Senior Statistician Markus Rapo from Statistics Finland.

The projections are calculated by the same rules for all municipalities, and allowances cannot be made for an individual municipality in them. Some municipality may have experienced development that clearly deviates from the usual in the projection period. Likewise, unpredicted development may take place in one of the factors influencing population development, such as immigration.

At the end of 2006, municipalities in Finland numbered 416, and the vast majority of them were small ones. In 362 municipalities the size of the population was under 20,000 and one in two, or 209 municipalities, had a population of under 5,000. According to Rapo, the prediction of development in fertility, mortality and migration and, consequently, in the whole population is, indeed, especially difficult for municipalities that are small in terms of size of population. The smaller the population basis, the larger the effects from random variation are on the projection.

"For instance, zoning a new residential area to the plan of a small municipality could mean that its migration gain in one year is as large as in the preceding ten years put together," says Rapo.

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Last updated 31.5.2007