ABSTRACT
A survey may be used to gather data in circumstances where little or no control over the value of variables of interest is possible. Statisticians begin with a brief and necessarily incomplete review of UK statistics; the general provisions are typical of what is available in countries of the Western world. Of the constituent countries of the UK, Northern Ireland had a considerable degree of devolved government but this has been modified in recent years pending resolution of Ireland’s partition problems. The 1920 Census Act specified that population enumerations should take place at intervals of not less than five years, conducted by the Registrars General of England and Wales, of Scotland and of Northern Ireland. In many countries, notably the USA, censuses are de jure. Although in 1981 a question was asked about usual residence, UK censuses are de facto, that is, individuals are enumerated on the basis of where they are at the time of the census.
