Quality

The purpose of this chapter is to give some practical illustrations of demographic data, showing how and in what form they are published and how their characteristics vary from time to time and from one country to another. Naturally, reference can be made only to some of the material collected in a few countries, most of it recent. An attempt is made, however, to give some idea of the range of variation, in quality, style and completeness of coverage, that can occur in population statistics between one area and another. As awareness of demographic problems increases, and more data are collected, this range is probably diminishing, and unreliable elements are slowly being rendered more trustworthy. Even where the basic aim is the same, however, the methods used for the collection of information vary because of the need to adapt them to local circumstances – political, legal or educational. Such circumstances may affect the way in which vital events are denned; they may also affect the accuracy of the statistics; if errors of interpretation are to be avoided, close attention must be devoted to both aspects.

World census coverage

Much valuable work has been carried out by the Population Division of the UN Organization in assembling information from all over the world on population size and characteristics. In this way, estimates for some 250 countries have been brought together. The results are shown in the UN Demographic Year Book, grouped into the six continental areas of Africa, America, Asia, Europe, Oceania and the USSR.