Changing methods of census enumeration
Preparations for holding a population census later this month are well under way. The census is a stocktaking of the country's most valuable asset: its people.
Census taking dates back thousands of years ago. Its concept existed as soon as a ruler felt the need to count his subordinates in order to assess his war potential or wealth. In the Book of Numbers, Moses and Aaron counted the congregation of Israel and the 20-year-old who were able to go to war.
History records also the population counts in Babylon, in China and in Egypt between 2800 and 2200 BC. These were limited to heads of households, males of military age and taxpayers. Women and children seem to have been excluded.
And each year we recall that the first Christmas occurred at a time when Caesar Augustus was conducting a census mainly for taxation purposes.
In the Middle Ages, apart for taxation and military services, censuses were taken for other purposes such as the apportionment of tithes and other political reasons.
As from the middle of the 17th century, censuses were conducted to collect information of a socio-economic character. In 1665, the census held in Quebec aimed at collecting data "on the number and conditions" of the population. Sweden followed 10 years later. Some countries, like the United States, have incorporated the census in their constitution.
It was only during the last three centuries, however, that the economic and social characteristics of a population were fully investigated in a census exercise.
Today, some of these characteristics are being left out since a lot of such data already exists through on-going or ad hoc surveys of all sorts.
Over the last 50 years, census data has become indispensable for researchers and administrators. Estimates of the future population and its age structure form the basis for planning for education, health, social security, housing and the labour supply.
For this reason, the International Statistical Institute met in St Petersburg in 1897 and proposed a "world census" for 1900. It was generally agreed that censuses should be taken every 10 years. Most countries abide by this norm, although there are some, like Ireland and Sweden, that take a census every five years.
The data collection is generally regulated by the UN Population Census Handbook, which first appeared in 1949. In the first half of the 1950s, censuses were held in 150 countries and about 2,000 million persons, estimated to represent 80 per cent of the world's population, were counted.
Census taking is not an end in itself. The questionnaire has to strike a balance between what is generally required for international comparative purposes and local conditions. Moreover, it has become a very expensive exercise. In the case of Malta, where enumeration does not present the problems that one meets in big cities, a census may cost something in the region of Lm1 for every enumerated person.
The high cost of a census exercise was one of the reasons that prompted several countries to revise and introduce other administrative practices and operation methods in the enumeration process that allow most or the whole collection of socio-demographic information from existing administrative records.
These take several forms, such as business and tax registers, social security, labour and education records, population and marriage registers kept by the local authorities and others. At present, some countries are also studying the possibility of having certain information provided through internet.
Until the 1970s, population censuses were traditionally taken by collecting information using census forms. Since then, several Scandinavian countries started to use administrative registers to revise and upgrade population estimates and other census information. Denmark was the first country to do away with the traditional methods and took a register-based census in 1981.
It is difficult to attempt a detailed classification of the methods being used by different countries. The traditional interview method is still operated in several countries like Turkey and most countries of Eastern Europe. A modified form of the interview method, where the interviewer checks and collects the forms completed by households, has been adopted in Malta and other countries like Israel and Portugal.
Other countries have a mix system where some data variables are collected through field operations and using the traditional census forms while others are extracted from administrative registers.
In the last censuses taken in Spain and Switzerland, the information extracted from existing administrative registers was pre-printed on the census forms and the respondents had to check it.
The censuses carried out in Denmark, Finland, Norway and the Netherlands do not involve any field operations. Sweden has adopted the register-based method for this year's census while Germany is testing the results of a pilot survey to assess the feasibility of a partial adoption of this system. It is claimed that this method is faster and much cheaper and does not impose any burden on respondents.
The change to a register-based census needs a lot of study and has to be introduced gradually. In Finland and Sweden it took about 30 years to set up and develop a totally register-based system. At present, several other countries are preparing to adopt this method.
In Malta, the non-availability of population registers does not allow estimates of internal migration. Moreover, the possibility of extracting census information of a demographic character from registers is limited. We have, however, a lot of social indicators resulting from recently-introduced surveys that would perhaps eliminate the need to collect this data during a census.
"The old order changeth, yielding place to new..." observed the good King Arthur. And census enumeration methods are no exception.
Mr Camilleri is chairman of the Malta Statistics Authority.