Study of Demography: Source of Demographic Data

BySanchana Siva Kumar

1.Abstract:

Demographic data comes from traditional sources like censuses, surveys, and administration records, which provide comprehensive information for policy and research. More recently, new data sources like “big data” from sources such as mobile devices, social media, and satellite imagery are being used to supplement and analyse population trends in new ways. Each source has advantages and disadvantages, and countries often use a combination of these methods. 

Demographers use demographic data taken from various sources to analyse population. A demographer is an expert in the study of statistics relating to the changing structure of human populations. It is well known that the three main sources of demographic and social statistics are censuses, surveys and administrative records. These three data sources are the principal means of collecting basic demographic and social statistics as part of an integrated program of statistical data collection and compilation.  Together they provide a comprehensive source of statistical information for policy formulation, development planning, administrative purposes, research and for commercial and other uses. While these three sources are complementary, many countries use a combination or all three methods for various reasons.  Normally, countries select one of these sources to obtain statistics based on the needs of the respective data users; reliability and timeliness of the results; and practicality and cost-effectiveness of the method. In many countries, however, a particular method is used due to statutory requirements.

Some main sources of demographic data collected by demographers are

1.1 Population and housing censuses:

Population censuses have been carried out in almost every country of the world during the past several decades, and some countries have conducted censuses for more than a century. The main reason censuses are carried out by so many countries is because a population census is the only data source which collects information from each individual and each set of living quarters, normally for the entire country or a well-defined territory of the country. Censuses must be carried out as nearly as possible at a well-defined point in time and at regular intervals so that comparable information is made available in a fixed sequence (United Nations, 1998).

1.2 Sample enumeration in censuses:

The cost and limited number of questions that can be included in the questionnaire are the main disadvantages of a population and housing census, so many countries carry out a sample enumeration in conjunction with the census to collect more detailed information on a separate (longer) questionnaire, often referred to as the “long form”. Collecting additional topics from a sample of population or households during the census operation is a cost-effective way to broaden the scope of the census to meet the increasing and expanded needs for demographic and social statistics. The use of sampling makes it feasible to produce urgently needed data with acceptable precision when factors of time and cost would make it impractical to obtain such data from a complete enumeration.

 1.3 Household sample surveys:

Household surveys are the most flexible of the three data sources. In principle, almost any subject can be investigated through household surveys.  With much smaller workloads than in censuses and the opportunity to train fewer personnel more intensively, household surveys can examine most subjects in much greater detail. While it is not possible to anticipate all the data needs of a country far into the future at the time a census is being planned, household surveys provide a mechanism for meeting emerging data needs on a continuing basis. As budgets for national statistical activities are always limited, the flexibility of the household survey makes it an excellent choice for meeting data

users’ needs for statistics which otherwise are unavailable, insufficient or unreliable.

1.4 Administrative records:

The third important data source that is commonly used in many countries is administrative records. The statistics compiled from various administrative processes can be very valuable to the overall national statistical system. Many social statistics are produced as a by-product of these administrative processes—for example, education statistics from periodic reports by the ministry of education, health Statistics from periodic reports based on hospital records, employment statistics compiled from employment extension services and so forth. Demographers use those sources to collect demographic data.

2.INTRODUCATION:

The term “Demography” is the statistical and mathematical study of the size, composition, and of spatial distribution of human population, and of the changes over time in these aspects through the operation of five processes of fertility, mortality, marriage, migration and social mobility. Usually, the demographic data are drawn from various sources such as national censuses, civil registration system as well as the sample surveys.

The three main conventional sources of demographic data are censuses, vital statistics, and sample surveys. A census captures a comprehensive snapshot of a population at a specific moment, offering detailed demographic, social, and economic data for the entire country. Vital statistics, collected through a civil registration system, provide a continuous record of crucial life events like births, deaths, marriages, and divorces. Sample surveys collect data from a representative portion of the population, offering a more flexible and cost-effective way to supplement census and registration data with specialized information. The integration of these complementary data sources allows demographers to build a robust and comprehensive picture of a population’s past, present, and future.

This data is crucial for demographic analysis, which in turn informs public policy, economic and market research, and social development initiatives.

 3.DISUSSION:

THE IMPORTANT SOURCES OF VITAL STATISTICS IN INDIA ARE:

  1. POPULATION CENSUS
  2. CIVIL REGISTRATION SYSTEM
  3. DEMOGRAPHIC SAMPLE SURVEYS SUCH AS THOSE CONDUCTED BY THE NATIONAL SAMPLE SURVEYS ORGANIZATION (NSSO)
  4. SAMPLE REGISTRATION SYSTEM (SRS)
  5. HEALTH SURVEYS, SUCH AS NATIONAL FAMILY HEALTH SURVEYS (NFHS)
  6. DISTRICT LEVEL HOUSEHOLD SURVEYS (DLHS-RCH) CONDUCTED FOR ASSESSING PROGRESS UNDER THE REPRODUCATION AND CHILD HEALTH PROGRAMME

3.1POPULATION CENSUS:

It is compiling, evaluating, analysing and publishing demographic, economic and social data pertaining, at a specific time, to all persons in a country or in a well-delimited part of a country.” In other words, the enumeration of a country or a region at a particular time is known as census.

The most important source of demographic data is the census. The word “census” is derived from the Latin word censure which means “to assess”. The New International Webster’s Dictionary defines it thus – “An official count of the people of a country or district including age, sex, employment, etc.” A United Nations Study defines the population census as the “total process of collecting, compiling and publishing demographic, economic and social data pertaining, at a specified time or times to all persons in a country or delimited territory.” Thus, a population census is an official enumeration of the inhabitants of a country with statistics relating to their location, age, sex, marital status, literacy status, language, educational level, economic activity, number of children, migration, etc.

Population census is a regular feature of all progressive countries, whatever be their size and political set up. It is conducted at regular intervals, usually every 10 years, for fulfilling well-defined objectives.

Salient Features of Census:

 A census has the following features:

 1. A census is usually conducted after an interval of 10 years.

2. The census covers the entire country or a part of it.

 3. The census operations are completed within specified dates.

4. It is organised and conducted by the Government through the Census Commission of the country.

5. For conducting the census, a reference period is determined by the Census Commission at that point of time.

6. A household or family is treated as a unit. However, in large census operations, migrant individuals and homeless persons are also enumerated at night at their places of rest or sleep.

7. Before starting the census operations, some preliminary steps are taken by the Census Commission such as preparation of schedules, lists of households in each area, training of enumerators, etc.

8. The filled-up census schedules are collected, examined and analysed statistically by the Census Commission.

9. The census data are published for circulation.

10. The census operations involve collection of information from households from door to door by enumerators. In some countries, schedules are sent by post and the required information is collected.

11. A census is a process whereby information is collected relating to age, sex, marital status, occupation, education etc. from people residing in a country.

12. Every country is legally bound to undertake a census after an interval of 10 years and people are bound to cooperate and provide the required information.

Uses of Census:

 Population census is very useful for researchers, administrators, social organisations, etc.

We highlight its uses as under:
  1. It provides primary population data relating to age, sex, marital status, economic activities, occupations, migration, literacy, etc.
  2.  Population data throw light on the socio-economic problems of the country such as the status of women, male-female sex ratio, population density, literacy level, urbanisation, living standards, etc.
  3.  These data help researchers, administrators, planners and social organisations to suggest and adopt measures to solve the various problems.
  4.  Census data are used for constructing life tables by insurance companies.
  5.  They are highly useful for making population projections.
  6.  Census data are used for carrying out sample surveys.
  7.  They are used by the Election Commission of the country for demarcation of constituencies and allocation of seats for municipal corporations, state legislatures and parliament of the country.
  8.  Population data are one of the bases of allocation of resources between the centre and states in a federal country.
  9. They guide the city planners in planning measures for the future growth of cities regarding their future needs relating to housing, transport, flyovers, sanitation, pollution, water, educational institutions, etc.
  10. Population projections and age-sex structure of the population help the government in estimating for the future military personnel of the country.

Some Problems of Census:

 Census operations are costly in terms of men, materials and money. They require huge manpower, piles of forms containing schedules and lot of money on them and on processing, preparing and publishing population data. The entire census work is also very time consuming.

 Besides, there are some other problems listed below:
  1. Census is not a continuous process and is usually conducted after 10 years. So, this is an ad hoc work which requires the training of census staff before each census. Thus, experienced staff is not available.
  2.  The enumerators often interpret the terms used in the schedules in their own way despite the guidelines supplied to them by the Census Commission.
  3.  In the census operations, the enumerators are required to go from door to door to collect information. This work is not only time consuming but also monotonous. Some enumerators who shirk work and are dishonest fill up the schedules with cooked up figures sitting at home.
  4.  Often many persons are reluctant to provide correct information for fear that it may be used for some other purposes. This happens if the household is illiterate or the enumerator is not able to convince the former that the entire information is kept secret by law.
  5. The household schedule pertaining to the census does not have any column about the number of family members who might have gone abroad.
  6.  In many developing countries, the column in the household schedule relating to age is based on age groups 1-5, 6-10, etc. thereby leaving a wide gap of 5 years. This creates a problem for the enumerator to fill up the age column which becomes a mere guess work. This is a defective method because age- specific information cannot be collected. In India and developed countries, age at the last birth in completed years is taken.
We may conclude with Barclay:

 “In practice, some people are always missing. It is impracticable to include all cases which belong to the universe. Some cases which ought to be covered according to rule are always omitted. On the other hand, some may be recorded more than once.”

HOW THE NATIONAL CENSUS IS TAKEN:

Census taking is a very complex and extensive task and is, therefore, usually conducted by governments. In many countries, provision for census taking is made by law. While such a law males the co-operation of each citizen mandatory, it also ensure that confidential nature of census information provided by individuals shall be preserved.

In India, census taking has been the responsibility of the government from the vary beginning. Even today, population census is a union subject, with the Ministry of Home Affairs in charge. A senior officer of the Indian Administrative Service, with experience in the conduct of census operations, is generally appointed as census commissioner. There are thousands of enumerators, with a hierarchy of officers at various levels in between. For each state and union territory, an officer, designated as the director of census operations, is appointed.

Taking into consideration the magnitude of the tasks, entire administrative machinery of the state and local self-government is placed at the disposal of the director of the census Operations. In rural areas, primary school teachers, village “patvaris” and other staff in local officers are generally appointed as census enumerators. The enumerator is the basic and the most important link in census operations. He has to visit every household within the area assigned to him and collect the required information.

3.2 Registration:

 Another source of population data is the registration of life or vital statistics. Every person is required by law to register with a specified authority such demographic events as birth, death, marriage, divorce, etc. Unlike the census, registration of vital events is a continuous process throughout the year.

It is an important source of information about citizenship, marital status, succession rights and settlement of disputes regarding birth and death.

 Registration is a secondary source of demographic data which is available from four sources:

(1) Vital Registration;

 (2) Population Register;

 (3) Other Records, and

 (4) International Publications.

They are explained as under:

3.2.1Vital Registration:

 Recording of vital events (or vital statistics) like births, deaths, marriages, divorces, etc. is obligatory on the part of every citizen in a country. For instance, the birth of a child has got to be registered with the municipal corporation of the town where the child is born in India.

Similarly, the occurrence of a death is required to be registered.

Such registration involves the filling up of a proforma with the following columns in each case:

 Birth Certificate: Name, Father’s Name, Mother’s Name, Age of Father, Age of Mother and Legitimacy.

Death Certificate: Name of the deceased, date of death, sex, race/caste, age of the deceased, place of death, cause of death, occupation, marital status, permanent residence, etc.

 In developed countries and in many developing countries, registration of marriage is also compulsory. But it is not so in India. Very few people want to register marriages with the Registrar of Marriages in developing countries like India. Bangladesh, Pakistan and Sri Lanka.

Similarly, in almost all the developing countries where the majority of people are illiterate and reside in rural areas, births and deaths are not reported to the registration authorities. Thus the registration records remain incomplete and are imperfect source of demographic data.

But this is not the case in developed countries where people are educated and record births, deaths, marriages, divorces, etc. with the appropriate authorities.

3.2.2 Population Register:

 This is another secondary source of collecting population data. A number of  maintain permanent population register for administrative and legal purposes.

It contains the names, addresses, age, sex, etc. of every citizen, of those who migrate to other countries and who enter the country. The population registers helps in verifying the correctness of the census figures for that year.

3.2.3 Other Records:

Besides the population register, there are other records which are secondary sources of demographic data in developed countries. They maintain population records to meet social security schemes like unemployment insurance and allowance, old age pension, maternity allowance, etc.

 In some countries, insurance companies maintain life tables relating to births and deaths and population trends. Selective demographic data are also available from electoral lists, income tax payers’ lists, telephone subscribers’ lists, etc. Though such administrative data are limited, they are helpful in providing for carrying out sample surveys.

3.2.4 International Publications:

Other sources of demographic data for the world and different countries are the United Nations Demographic Year Book and Statistical Year Book. The World Health Organisation (WHO) publishes a monthly journal Epidemiological and Vital Records which gives data on public health and mortality of different countries.

The United Nations Development Programme (UNDP) in its Human Development Report and the World Bank in its World Development Report publish annually demographic data relating to population growth, projections, fertility, mortality, health, etc. for countries of the world.

3.3 Sample Surveys:

 Sample survey is another source of collecting population data. In a sample survey, information is collected from a sample of individuals rather than from the entire population. A sample consists of only a fraction of the total population. Several different population samples can be drawn on the basis of sample surveys such as the number of abortions, contraceptives used, etc. for the study of fertility.

Some countries conduct national sample surveys based on Random Sampling or Stratified Random Sampling. Whatever method is adopted, care should be taken to select a representative sample of the total population. The survey of the sample requires a small trained staff and small questionnaires relating to one aspect of the population. The data so collected are tabulated, analysed and published.

 So this method takes less time and is less costly. Sample survey can be used to supplement the census data and to carry out further the trends in population growth in between two census operations. Sampling is also used to check the accuracy of the census data where there is doubt in census results. This method yields good results if the sample is properly chosen.

Limitations:

The sampling method has certain limitations.

  1. It is highly subjective and it is possible to arrive at different data with different samples of the same population.
  2. There are bound to be errors in coverage, classification and sampling of population data.
  3.  As the survey requires many surveyors who may not be efficient and sincere, it is subject to large errors.
  4.  If the informants in the sample do not cooperate with the surveyors, the survey will not give accurate results. To conclude with Stephen, “Samples are like medicines. They can be harmful when they are taken carelessly or without adequate knowledge of their effects.

 

4.Conclusion:

 The study of demography relies on a combination of data sources like censuses, civil registration, and surveys, each with unique strengths and weaknesses, to understand population dynamics. Accurate demographic data is vital for informing policy, planning public services, and driving economic and social development, and the integration of modern data sources like big data is transforming the field. Ultimately, a multi-source approach is necessary to get a comprehensive and reliable picture of a population. 

Demographic data is data one of the essential characteristics of the population. This includes age, gender, and income as well. It is used in nearly all the fields of a country for estimating their customers and their characteristics. The prevalent research methods like civil registration systems, census, and sample surveys are some of the most common and popular research techniques. Each of these has many advantages and disadvantages, like in the civil registration system; the data may not be updated timely, leading to wrong evaluation.

In the census method of research, the surveyors are supposed to reach door to door, which is highly time-consuming and monotonous, leading them to act disloyal and not provide truthful information to their superiors. In the sample survey method, the chosen samples may be inappropriate and not lead the surveyors to the best results. Seeing the importance and need of accurate demographic data, a lot of newer research methods are being launched, which can reduce the hard work of the organisations and ease the process with less or no involvement of humans and other expensive sources.

The study of demography depends on a combination of primary sources (census, vital registration, surveys, population registers) and secondary sources (administrative records, special studies). Each has its strengths and weaknesses, but together they provide a comprehensive picture of population dynamics. Accurate demographic data is essential for planning development policies, health care, education, housing, and employment.

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