Linking the Indian Census to the National Sample Survey
Total Page:16
File Type:pdf, Size:1020Kb
Linking the Indian Census with the National Sample Survey* Mamta Murthi Clare Hall, Cambridge P V Srinivasan IGIDR, Bombay S V Subramanian Institute for the Geography of Health, University of Portsmouth Draft: June 1999 * We are grateful to Jean Drèze for detailed suggestions and comments. 1 Introduction This paper discusses why it is useful to augment district-level information in the Census of India with regional consumption and poverty estimates from the National Sample Survey. It provides an illustration of how the two sources of data might be brought together by linking district lists from two recent Censuses (1981 and 1991) with regional poverty estimates from three rounds of the NSS (1972-73, 1987-88, and 1993-94). 2 The need to augment the Census The Census of India is a rich source of information on demographic and other socio-economic variables. Conducted every decade since 1871, the Census provides perhaps the longest time-series on social and economic change in India.1 In addition national and state level aggregates, the Census contains detailed information at the level of the district (the basic unit of administration) and, in many instances, lower levels of disaggregation such as towns and wards (in urban areas) and blocks and villages (in rural areas). As a result, the data allow us to look at a number of issues, including population growth, births, deaths, female-male ratios, education, occupation, and urbanization, and how and why they vary over time and space, using the district as the unit of analysis. In the area of population and demography, it is difficult to over-emphasize the importance of the Census. The system of civil registration of births and deaths in India is simply too incomplete to provide an accurate estimate of vital rates (see Government of India, 1972 among others). As a result, the Sample Registration System (SRS) was set up in the late 1960s to provide reliable and timely vital statistics, and starting from 1971, the Census was expanded to include questions on fertility and child mortality. The SRS and the decennial Census remain the only two nation-wide sources of information on these questions.2 Of the two, only the Census provides information at the district-level. The need to cover the entire population and range of issues covered in the Census introduces a greater scope for error. Remarkably, the two sources provide estimates of vital rates which are broadly similar (see e.g. Government of India, 1983, 1988a). One of the major difficulties with using the Census for district-level policy analysis is that it contains no information on income, consumption levels, or poverty. Although a number of variables can be used as proxies for per-capita income or 1 For two excellent perspectives on the Indian Censuses see Natrajan (1972) and Srivastava (1972). 2 The National Sample Survey (NSS) collected information on population questions from 1958-68, and a comprehensive module on fertility, family planning, and mortality was included in the 28th round of the NSS (1973-74). However, plans to repeat the module at regular intervals were dropped when comparative studies of the NSS and SRS revealed that the NSS suffered from significant omissions. See, Government of India (1981) and Rama Rao et. al. (1987). The recent National Family Health Survey (1992-93) and its successor survey (currently underway) are an alternative source of estimates for the 1990s. consumption (such as urbanization, or the proportion of agricultural labourers in the total population), these are a far cry from the fairly detailed information on individual consumption and expenditure collected through household income and expenditure surveys. As a result, it is difficult to control for per-capita income or poverty when conducting district-level analysis using Census information. One way around this problem is to import information on income or consumption from other sources. The principal source of information on household consumption in India is the National Sample Survey (NSS). The NSS does not sample from every district in the country. However, sample sizes are reasonably large at the level of the NSS region, which is an intermediate unit between a district and a state. This opens up the possibility of using NSS region-level estimates of consumption and poverty in conjunction with Census data. Indeed, this is the approach employed in Murthi, Guio, and Drèze (1995) and Drèze and Srinivasan (1996). Matching information from the NSS with the Census involves the very practical question of knowing which Census districts comprise which NSS regions. Moreover, constructing a time-series involves keeping track of changes in the boundaries of both Census districts and NSS regions. This paper documents how a consistent time-series can be constructed for the two most recent Censuses as a particular illustration of how the Census and the NSS can be used together. 3 The rest of the paper is organized as follows. The next section describes how district lists from the 1981 and 1991 Censuses can be put together, while Section 4 discusses the changing composition of the NSS regions over three rounds, 1972-73, 1987-88, and 1993-94. Section 5 concludes. 3 Matching districts across Census years: 1981 and 1991 The spatial units (e.g. districts, towns etc.) at which Census information is compiled owe their existence to administrative functions other than the Census. As a result, their boundaries change over time, in response to administrative requirements and/or political need. Typically, the number of districts has increased over time, with districts tending to be partitioned rather than merged. This process of carving out new political and administrative ‘spaces’ has accelerated somewhat in the 90s. For example, newspaper reports suggest that the number of districts in Uttar Pradesh will be in the range of 90 for the 2001 Census from the present total of 63. The main problem confronting any researcher who wants to use the 1981 and 1991 Censuses to conduct district-level analysis is the partitioning of districts between the two Census years (see Table 1). As a result, there were 466 districts in 1991 compared to 412 districts in 1981.4 A further problem is that some districts retain their 3 There are other problems that arise in creating a consistent time-series, e.g., changes in definitions across years. However, these are not the focus of this paper. 4 These figures include states which were not covered by the Census in particular years. No Census was held in Assam in 1981, and in Jammu and Kashmir in 1991. To obtain the total for 1981, we names even when their boundaries have changed. For example, the 1981 district of Ambala in Haryana split into two districts, called Ambala and Yamunanagar, in 1991. Table 1 States where district changes took place between 1981 and 1991 States5 Number of districts 1981 1991 Arunachal Pradesh 9 11 Assam 10 23 Bihar 31 42 Goa 1 2 Haryana 12 16 Karanataka 19 20 Kerala 12 14 Maharashtra 26 30 Manipur 6 8 Rajasthan 26 27 Tamil Nadu 16 21 Uttar Pradesh 56 63 West Bengal 16 17 India 412 466 In general, the best source of information on district boundary changes are the Census Atlases introduced in the 1961 Census (see, for example, Government of India, 1988b for changes that took place between 1971 and 1981). A more time-consuming alternative is to compare district boundaries across Census years using the District Census Handbooks, of which there is one per district. However, to the best of our knowledge, no Census Atlas has been produced for the 1991 Census and a full set of Handbooks for the 1991 districts is yet to be compiled. We therefore compared all- India administrative division maps for 1981 and 1991 in order to establish changes. All-India administrative division maps are provided on the scale of 1 cm to 100 km (1:100,000). The 1981 Census Atlas contains the all-India administrative division map for 1981. For 1991, a similar map was made available by the Census in its early publications (e.g. Government of India, 1992). Using the all-India administrative division maps, we matched 1981 districts to 1991 districts. This ‘mapping’ is reported in columns 1 and 2 of the Appendix.6 Most of the district changes between 1981 and 1991 are relatively simple (see Table 2). In most cases, one 1981 district was bifurcated into two 1991 districts. For example, the added the number of districts in Assam (10) to the actual number of districts covered by the 1981 Census (402). Likewise, to obtain the total for 1991, we added the number of districts in Jammu and Kashmir (14) to the actual number covered by the 1991Census (452). 5 The term ‘state’ includes Union Territories which were accorded the status of states by the 1991 Census (e.g. Arunachal Pradesh and Goa). 6 Our ‘mapping’ is based on sources that were available at the time of writing and may be subject to minor revision after the 1991 Census Atlas is published. 1981 district of Osmanabad in Maharashtra was partitioned into two 1991 districts, Osmanabad and Latur. In nine instances, the 1981 district was bifurcated into three or more 1991 districts (e.g. Ranchi of 1981 became Lohardaga, Gumla, and Ranchi in 1991). Finally, there was one instance where a 1991 district (Panipat in Haryana) was created from two 1981 districts (Karnal and Kurukshetra).7 Table 2 Nature of correspondence between 1981 and 1991 districts Outcome (1991) Source (1981) Number of cases One 1991 district = One 1981 district 368 Two 1991 districts = One 1981 district 33 Three or more 1991 districts = One 1981 district 9 One 1991 district = Two 1981 districts 1 In using the information in the Appendix to construct a time-series involving district-level estimates of particular variables (e.g.