International publications
The United Nations and its various organs, along with other international agencies such as the World Bank, publish population data for the world and for different countries at regular intervals. The most important of them is the Demographic Year Book, published by the UN. It provides data on such wide-ranging topics as population size, area, density, percentage urban population, population growth, age-sex composition, number of births and birth rate, number of deaths and death rate etc. Sometimes the volume is devoted to special topics, which include fertility, mortality, marriage, divorce, migration, and population census statistics. The special volume includes detailed statistics regarding the topic. Besides the year book, the UN also publishes the Population and Vital Statistics Report quarterly which includes the latest data on total population, total mid-year population and estimate of population for a recent reference year (Srinivasan, 1998b:56). Information on vital events includes total number of births, deaths, infant deaths, crude birth rates and crude death rates.
The United Nations Development Programme (UNDP) also publishes data on various social, economic and demographic aspects for the world and for different countries in its annual volume on Human Development Report.
Other international publications on world population data include Production Year Book of FAO, Year Book of Labour Statistics of ILO, Statistical Year Book of UNESCO, World Population Datasheet of Population Reference Bureau (PRB) and World Health Statistics Annual of the World Health Organisation (WHO). While the FAO publication provides information on agricultural population, the Labour Statistics of ILO gives detailed data on the economically active population. Similarly, the UNESCO publication provides data on education, literacy and school attendance for different countries of the world. The monthly periodical ofWHO presents data on public health and mortality for different countries of the world. Apart from these sources, the World Bank also publishes data on various demographic, social and economic aspects in its annual volume entitled World Development Report.
Population data in India
As elsewhere in the world, data for population studies in India are obtained from census enumeration, vital registration and sample surveys. In the following sections a discussion on these sources and the nature of data is presented.
Population census
The first attempt to obtain the size of population in India was made during 1867- 72. But this census counting was not synchronous, as it was not conducted at the same time in different areas. It did not cover the whole country also. However, as remarked later by Kingsley Davis, a famous demographer, this attempt was ‘an auspicious beginning of census taking in India’. From 1881 onwards, census counting has taken place on a synchronous basis at an interval of every 10 years. The 2011 census is the 15th in the series and the seventh after independence. There are very few countries in the world with such a record of an unbroken series of decennial censuses (Bose, 2001). Up to 1931, the Indian census had adopted a de facto approach wherein enumeration was undertaken throughout the country on a single night. Obviously, apart from being very costly this method required deployment of an extremely huge army of enumerators. Hence, from 1941 onwards, the country switched over to an extended de facto canvasser method in which data are collected from ever)' individual by visiting the household and canvassing the same questionnaire all over the country over a period of two to three weeks (RGI, 2011:4).
For a large and extremely diverse population like that in India, conducting a population census is a daunting task (Bose, 2001). Census enumeration is perhaps the largest administrative exercise in the world. The responsibility of conducting the decennial census rests with the Office of the Registrar General and Census Commissioner, India, under Ministry of Home Affairs, Government of India. Its main responsibility is to conceive, plan and implement census taking in the country. It is a union subject with the Ministry of Home Affairs in charge. A senior officer of the Administrative Sendees, with experience in census operation, is appointed as the Registrar General and Census Commissioner. Similarly, for each state/union territory an officer designated as Director of Census Operation is appointed. The responsibility of actual counting rests with thousands of enumerators who are drawn from primary and other schools, village patwari (in case of rural areas) and local offices. An enumerator is required to visit every household within the area allocated to him for collecting required information. The Indian Census Act of 1948 authorises the enumerators to ask the prescribed questions, and the respondents are legally required to furnish the details truthfully.The Act guarantees that the collected information will be confidential, and used only for statistical purpose, and not as evidence even in the court of law.
It may be of historical interest that although the population census of India is a major administrative function, the Census Organisation was set up on an ad- hoc basis for each census till the 1951 Census. The Census Act was enacted in 1948 to provide for the scheme of conducting population censuses with duties and responsibilities of census officers. The Government of India decided in May 1949 to initiate steps for developing systematic collection of statistics on the size of population, its growth etc., and established an organisation in the Ministry of Home Affairs under the Registrar General and ex-Officio Census Commissioner, India. This organisation was made responsible for generating data on population statistics including Vital Statistics and Census. Later, this office was also entrusted with the responsibility of implementation of the Registration of Births and Deaths Act, 1969 in the country.
The task of census taking begins with the notification of the government. A draft questionnaire is prepared and discussed in the ‘Census Users’ Conference’ for finalisation. A pre-test in the form of a pilot survey is undertaken all over the country before finalisation of the questionnaire. Enumerators are appointed for the purpose and arrangements are made to provide training to enumerators along with all other functionaries. As a preliminary to the census counting, each house - residential or non-residential - is numbered and a list is prepared a few months prior to the actual enumeration. The house-list forms an important component of the enumeration as it provides a frame for the actual counting. It is used for collecting data on housing and household amenities. In order to facilitate house-listing, detailed ‘national maps’ and layout charts of all villages and towns are prepared. Finally, on the day of counting, the enumerators visit the households in areas allocated to them and collect data with the help of specially designed schedules. At the time of the 1991 census,‘household schedules’ and ‘individual slips’ were used for the purpose. In the 2001 census, two schedules - one for ‘house-listing’ and another for‘population enumeration’were canvassed.The same was continued in 2011 also.
For the 2011 census, the house-listing phase began on April 1,2010, and continued up to September 30, 2010. ‘Population enumeration’ was undertaken during the period February 8-28, 2011. A revisional round, as part of the post-enumeration check, was conducted during March 1-5, 2011, to adjust the figures for changes taking place between the exact time of the visit of enumerator to the household and 00.00 hours of March 1,2011. It may be noted that the census data pertain to a well-defined point of time called a census moment. For the 2011 census, 00.00 hours of March 1,2011, was the census moment.
A Post-Enumeration Check (PEC) is conducted immediately after the actual counting is over. This is designed to assess the level of accuracy of the count in terms of the ‘coverage’ and ‘content’ errors. Based on appropriate sampling procedures, PECs have formed an integral part of the census enumeration in the country' since independence. PECs help in ‘identifying areas that would need attention such as concepts and definitions employed, procedures of enumeration and related instructions to the field staff, etc. as well as in improving the conduct of future censuses. No attempts, however, are made to adjust the Census results based on the PEC results’ (RGI, 2011:25).
Soon after the actual counting is over, the census organisation gets involved in the task of tabulation and publication of data. Initially, the preliminary results are announced and ‘provisional’ tables on aspects of immediate interest to researchers and planners are released. The same for 2011 was released by the office of the Registrar General and Census Commissioner on March 31,2011, with perhaps the shortest time lag between actual counting and publication in the census history of India (Navaneetham and Dharmalingam, 2011).This is followed by publication of detailed final results.The census data are brought out in different volumes or tables, of which the most commonly used by population geographers are Primary Census Abstract (PCA), General Population Tables (А-Series), General Economic Tables (В-Series), Social & Cultural Tables (С-Series), Migration Tables (D-Series), Fertility' Tables (F-Series) and Special Tables for Scheduled Castes & Scheduled Tribes (SC & ST Series). These tables are published at two levels: while the office of the Registrar General publishes ‘all India’ volumes, which provide state-wise data, the Directorate of Census Operation publishes data pertaining to lower-order administrative divisions i.e. districts, tehsils and blocks of the respective state.
The census provides data on a wide range of demographic, social and economic aspects. The demographic aspects on which data are available include size and distribution of population by sex and age for rural and urban areas separately. It also includes some information on fertility aspects such as number of births during the preceding year to currently married women, and children ever born and surviving related to ever married women. On the social aspects the information provided pertains to distribution of scheduled castes and scheduled tribes, population by religion, languages spoken, marital status, levels of literacy and educational attainment etc. They are given for males and females in both rural and urban areas separately. Likewise, on economic characteristics, the census provides data on workforce participation by sex and by broad age groups and distribution of workers in different industrial categories for males and females and for rural and urban areas, among others. These data are also available for scheduled castes and scheduled tribes separately. The 2001 census provided data on these economic characteristics along with levels of literacy and educational attainment for different religious groups also. This practice has continued in the 2011 census also. The 2011 census has, for the first time, provided data on population of transgender in the country. It may also be noted that the 2011 census has collected data on ‘caste’ after a lapse of 80 years on demand from various walks of life. Census of India collected data on ‘caste’ up to 1931 and thereafter it was discontinued. Migration or spatial mobility holds a very important place in the study on the dynamics of population change of any area. The census remains the single most comprehensive source of data on migration in the country. It provides data on volume of migration by sex and rural-urban status (both at the place of origin and the place of destination) on the basis ofplace of birth’ and ‘place of last residence’ criteria. Migrants are further classified on the basis of'dura- tion of residence’ at the place of enumeration. From the tables on migration data, a researcher can generate data on volume of migration in different streams and different distance categories. These are available for all the states/UTs and the districts of respective states. The census also provides information on reasons of migration, which was started in the 1981 census and has continued in subsequent censuses. The census also provides information on the characteristics of migrants in terms of their literacy status, levels of educational attainment, working status and distribution in different industrial categories at the place of destination for all the million-plus cities of India. In addition, the census provides information on houses, household amenities and assets separately for female-headed households and the slum population.
