Sources of Population Data 

Population data mean the statistical information related to population and its determinants. In order to analyze the situation of population at any place, we need basic information of population situation and its characteristics features. Population data provide such necessary information required to diagnose the specific population traits and characteristics. It also helps to predict the future characteristics as well. Data and information related to population situation of certain place can be obtained from different sources. The sources that provide such information about the population situation, characteristics of population and the determinants of population are called sources of population data. They are mainly categorized into primary and secondary sources. 

Primary source of population data 

The sources which provide the first-hand population data collected people themselves are known as primary sources of population data. Main procedures related to primary sources of population data are census, survey, observation and ocular study, etc. 

We describe some of main primary sources of population data as given below: 

1. Census
2. Vital registration 
3. Sample survey 
4. Administrative records 
5. Population register 

i. Census 

 It is ccnsidered as the major source of population data. It includes many process. It helps to find out population status of a country or any other area. In some country, it is taken in 10 years whereas in some countries it is taken in 5 year interval. In 1970 AD, UNO has defined census as a total process of collecting, compiling, evaluating, analyzing, and publishing demographic, economic and social data pertaining at a specified time to all persons or a country or in a well-defined part of the country. 

History of Census 

Census is said to have started in very primitive society. In ancient time, census was primarily taken to find out the tax-payee people and amount of tax collected. But nowadays, census has many perspectives and widely used with many purposes. Historical trend of census can be studied from the table below: 

History of Census in Ancient Time
Places	Census Year
Bolivia	4000 BC
China	3000 BC
Egypt	2500 BC
India	330 BC  (During the time of King Ashoka)

 

The modern census is considered to have begun from 1665 AD. It was started at that time in New France and Acadia (Canada)/ Modern census includes many new techniques of census procedures. Modern census started in many countries in different times. Some of them are listed below: 

Modern Census in the world
Places	The first Census Year
New France	1665 AD
Acadia (Canada)	16665 AD
USA	1790 AD
Britain	1801 AD
India	1872 AD
Nepal	1911 AD

 

Methods of census

Census can be taken in different ways. Major three ways of taking census are described below: 

a) De facto method 

It is an old method of census. It was first practiced in Britain. It is a method of census in which the people are enumerated within one night called census night wherever they are found. In this method, people are informed to live their respective places so that enumerators can meet them. The census night usually determined in the full moon night of autumn or spring season. 

b) De jure method 

It is a modern method of census. It is used all over the world. It is a method of census in which the population data are enumerated at the permanent resident of people; not at the temporary residence. However it takes two or three weeks, it is practicable and regarded as scientific) It can have more reliable data and easier method as it is done during daytime. 

c) Modified De jure method 

It is very similar to De-jure method of census. But, the usual residence is taken instead of the permanent residence. The usual residence means the place with a person is living for at least six months. From the census of 1952-54 BS, this method has been followed in the census of Nepal. This method of census is followed by most of the countries nowadays. 

Differences between de-facto and de-jure method of census 

De-facto method	De-jure method
i. People are counted wherever they are found.	i. People are counted in their permanent residence.
ii. It is held at night.	ii. It is held during day time.
iii. It is not in practice nowadays.	iii. It is widely practiced in most of the countries of the world.
iv. It needs low cost and less time.	iv. It costs higher and takes long time.
v. It is a non-scientific method of census.	v. It is regarded as a scientific method of census.
vi. The outcomes are less reliable.	vi. The outcomes are less reliable.

 

Features of Census 

Major characteristic features of census are listed below: 

1. Census is the key source of authentic and reliable data related to population and demography. 
2. Census provides several data like age, gender, occupation, language, religion, birth, death, migration etc., related to population 
3. Census is taken and controlled by the government of concerned state or country. 
4. Census is held within the pre-determined duration of certain period) 
5. Census is held after an interval of certain time period) (Generally of five or ten years) 
6. Census primarily collects the first hand data from individuals. 

Data collected in Census 

The contents or the information collected in censuses in various countries are almost similar. UNO has recommended a list of contents for carrying out census. Most of the countries follow the same guideline recommended by UNO, which includes geographical, economic, personal and household characteristics as given below. 

a) Geographical characteristics 

1. Resident at the time of counting. 
2. Place of birth, rural or urban 
3. Place of previous residence 
4. Place of usual residence 
5. Duration of residence 
6. Place of work 

b) Economic characteristics 

1. Occupation 
2. Industry 
3. Main source of Income 
4. Income from various sources 
5. Employment status 

c) Personal characteristics 

1. Age 
2. Sex 
3. Marital status 
4. Age at marriage 
5. Order of birth 
6. Mother tongue and other languages known 
7. Literacy 
8. Educational attainment 
9. Citizenship 

d) Household characteristics 

1. Name of the head of the household and rest of the family members and relationship with the head of the household. 
2. Individual living in the household and not related with the head of household 
3. Living children 
4. Religion 
5. Caste\ Ethnicity 
6. Number of children ever born. 
7. Number of live birth and death occurred during 12 months previous to the census year. 

Advantages of Census 

Census is very essential to obtain necessary information required for good governance and formulation of developmental plans and policies of a country. Some of the major advantages of census are listed below: 

1. Census provides various data related to population situation of a country. Total population, population density, distribution of population, population management, population composition, economic status of people etc. are some of the major  information provided by census. 
2. Census provides necessary data required for the formulation of developmental plans and policies of a country. 
3. Census help in shaping political activities and developing the action plans related to public concerns. 
4. Census is an opportunity to bring the governing units of a country or state closer to their people up to the grassroots level. 
5. It is necessary to analyze the status of quality of life and known the information related to status of people. 

ii. Vital registration 

It is the registration of vital characteristics of people. It is regarded at authorized government offices. Municipalities and village development committees (VDC) keep records of vital registration =. It is also called partial registration because it  keeps an specific item of demographic data like birth, death, migration etc. up to data. Different demographic events are recorded separately in this system. 

"Vital registration is a legal registration, statistical recording, and reporting of the occurrences of vital demographic events like birth, death, marriage, miscarriage, stillbirth, abortion, fetal death, annulment, divorce, immigration and emigration. " 

It is considered as a reliable source of population data. After recording the vital events once, the recorded data are revised annually to find estimated changes to make it updated. People must have necessary awareness regarding vital registration so that they become motivated by themselves to record their vital demographic events. 

Vital registration was first started in Britain in the 16th century. At that time, the Churchman used to maintain the records of vital events. In 1563, there was a provision of vital registration within the churches of Roman Catholics. Similarly, in 1837, Britain passed a Registration Act for vital registration procedure. 

In 1608, Sweden started vital registration on the basis of modern concepts and techniques.  This was the first scientific vital registration. Following table shows the historical trend of scientific vital registration in different countries. 

Historical trend of modern vital registration
Country	Year of the first vital registration
Sweden	1608 AD
Canada	1610 AD
Finland	1628 AD
Denmark	1646 AD
Norway	1684 AD
Nepal	1978 AD

iii. Sample Survey 

Sample survey is defined as a process of collecting, compiling, evaluating, analyzing, and publishing population data of a sampled population for generalizing the result to the total population. 

Sample survey is also called partial census. It is because a small portion of population is taken under study in the sample survey. The study result of small portion of population is generalized to the total population. As in census, a list of questionnaire is prepared and data is collected from the selected or sample houses or people. It was first started in Britain in the 19th century by Mr. Charles Booth. In the beginning of the 20th century, Mr.B ) W. Rowntree used this system to study on the demographic components in Britain. After 1950, the system is found to be remarkably in many countries. In 1956, Population Research Center was established in Princeton University and the center carried out more than 400 demographic studies with the of sample survey. Nowadays, this method is widely used all over the world. It is an faster, easier, and economical method of finding out population characteristics. Both longitudinal and cross-sectional methods of surveys are used in Nepal according to the needs, requirements and demographic characteristics. 

iv. Administrative Records 

Administrative units and organizations keep different population data for their different purpose. there are some organizations which are formed to keep and manage data. Central Bureau of Statistics of Nepal keeps records of various types of data and makes these data available to others. Almost all organizations keep their related data in their administration. School keeps records of teachers, students and staff. Industries keep record of employees, staff, clerks, and workers. 

Similarly, other records like voter's list, population register, service statistics, citizenship records, records of old people, telephone directory, patients list in hospitals, etc. are some examples of administrative records. 

v. Population register 

Population register is the system of recording all the demographic events like birth, marriage, migration, education, occupation, etc. of each individual. It is also called universal registration because it keeps all population data up to date for each individual. It is comparatively a complex and expensive process. It provides details about population dynamics. Belgium, Bulgaria, Germany, Ireland, Iceland adopted this method to keep population data up to date nowadays. 

Secondary sources of population data 

The population data derived from other sources like books, journals, magazines, research reports, population monographs, administrative records etc. and make such data available to others are called secondary sources of population data. It is also called second hand population information. 

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