1. It must be conducted by government of the state or country where the census is taking place.
2. It must be conducted at the same time (simultaneously) throughout the country.
3. It must involve regular counting at specific intervals of time, eg, United state of America’s population taken in 1790, 1800, 1810, 1820… 2010 which is an interval of 10 years.
4. It must reveal the population of a country at a specific period of time e.g America’s population census as of 1790 was 3,929,214; as of 1890, it was 62,979,766; as of 1990, it was 248,709,873.
5. It must involve the physical counting of people rather than by proxy.
6. It must involve experts who are knowledgeable in population studies and they must be of high integrity.
Types of population Census
There are two main types of population census and they are:
1. Defacto Population census: This is the type of population census which involves the counting of only those who are present physically during census. In this group, only those who are present physically or seen are counted.
2. De jure population census: This is the type of population census which involves the counting of people who have been permanent residents of a specific area. It does not matter whether the person is present of not. This is population census commonly referred to as counting by proxy.
Importance or Reasons of Population Census
The importance or reasons for conducting a population census include:aiding the government to know the number of people living in the country and the structure of the population; helping in the determination of taxable adults so as to know the amount of revenue expected from that sector; enabling the country to forecast her future economic needs eg, housing, food etc and the provision of statistics to the government to determine the level of unemployment in the country
Further importance could be: its assistance in the determination of the standard of living of the people in a country through per capital income; using the statistics of the number of people in a country to formulate economic policies eg, revenue formula is at times based on population figures; the estimation of the number of immigrants in a country, the assistance to the government in the distribution of resources eg, areas of high population will get more resources than areas of Low population; giving the government an idea of the different population in various parts of the country and this can help in the provision of social amenities like housing, water, electricity, roads, schools, hospitals etc. It doesn’t just end there, Population census is also very vital in giving detailed information to the government on areas of the country where population per land area is high or low; reveals level of man power by helping to reveal the total number of people who are working-when the level of manpower is high, the economic development of the country is assured and assists international agencies and governments in giving aids and other assistance to countries; assists international investors in making investment decisions. In some developing nations, Population is often used to allocate parliamentary seats. States with high Population are given more parliamentary seats than states with low population.
So all said and done, population census as we can now see is far beyond just counting the population of a particular area at a particular time. It can go a long way in helping an area’s or nation’s economy to grow even as it varies from one year to another.