A census is a count of the population of a country. A census also finds out facts about the population, such as their age, sex, jobs they do, type of house and what language they speak. It is usually carried out every 10 years. A country will carry out a census because

1. The government needs to know how many people live in each part of their country; it then knows where to spend its money
2. They also find out about population trends; this allows them to plan ahead
3. They can find out about the population structure - how many old, middle aged and young people there are; this again allows the government to target their spending - on, for example, old folks homes or schools

Census Difficulties

Some countries have a lot of difficulty carrying out censuses and some countries don't have censuses at all. The reasons for this are

• They cost a lot of money which poor countries can't afford
• Some people live in difficult to reach areas because of mountains, deserts and forests
• Wars make counting difficult
• Nomads (people who move about) also make counting difficult
• People who are illiterate (can't read or write) are unable to fill out the forms
• Some people do not tell the truth for political or religious reasons

Vital Registrations

This is a method of counting the population by carefully using the records of births, marriages, adoptions, divorces and deaths. This method is cheaper, but it does not give as much information as a census. It does, however, give a continuous record, whereas a census gives a "snap-shot" picture every 10 years.

Another way is by a sample survey where a fraction of the population are surveyed. This method has the advantage of being cheaper than a census, but the disadvantage of being less accurate.