1.8 Main branches of demography

Demography can be divided into two main branches:

Descriptive demography looks to other traditional disciplines - sociology, economics, social policy, etc. - in its search for answers to changes in population phenomena. It aims to find out why the number of births has decreased, why the number of divorces in Finland is higher than in many other countries, and why people move from rural into urban areas.

Changes in demographic phenomena can also be explained on the basis of changes taking place in society: for example, how does the level of education influence the number of children born, do women with more education have fewer children than women with a lower level of education? On the other hand, researchers may also be interested to study the impacts of demographic phenomena on society: for example, how does high population growth influence socio-economic development, does migration into urban areas support development in these areas, what are the effects on the countryside?

Mathematical or formal demography, then, employs mathematical formulae and models to describe population changes. This is known as demometry or the measurement of demographic phenomena. The most common approach is to compare some vital event to the size of the population, for example. To generalise, it can be said that demography is largely an exercise in calculating various ratios and in comparing these ratios with one another either at a certain point in time or within a certain period of time.

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