Population of India in a non census year: 2017

A quick look at the world wide web does not give any clarity on population estimates for non-census years for India. Besides, agreeing on a single estimate, subgroup consistent estimates can help in the designing and planning of public policy initiatives for vulnerable communities. The Ministry of Home Affairs (Office of Registrar General), the Ministry of Health and Family Welfare and the Ministry of Statistics and Programme Implementation should come together to take this forward.

Curious

I was curious to know of India's population in a non-census year, 2017. The need arose, as I wanted to estimate snake bite rates (SBRs) across states by gender for 2017. I will address that in a different note, but for now I would like to comment on my search for an estimate of India's population in 2017.

Technical Group of 2006

My search took me to the Statistical Year Book of India 2017 available through the Ministry of Statistics and Programme Implementation (MOSPI), as also the National Health Profile of India - 2018 (released in June 2018 by the Central Bureau of Health Intelligence, CBHI). Both these documents provides population estimates for 2017 based on a Report of the Technical Group on Population Projections (TGPP) published in 2006. The report used census 2001 as base to estimate population rounded-off to the nearest '000 on  1 March for the years 2001 through 3026. The TGPP estimate for India in 2017 being

• 1,283,600,000 (or, 1.28 billion), for 1 March 2017.

CSO implied estimate

Recently, on 31 May 2018, a press note was released on provisional estimates of annual national income for 2017-18 and revised estimates for earlier years in 2011-12 prices by Central Statistics Office (CSO). In this, one has data for Gross Domestic Product (GDP) and per capita GDP for financial years (starting 1 April of year 't' to 31 March of year 't+1'). While there are no explanation on the method for computing population and the population estimates, one assumes that the per capita GDP ought to have been calculated by taking into consideration the population on 31 March of year 't+1'. The Handbook of Statistics on Indian Economy (in notes to macroeconomic aggregates) points out that for 2011-12 series population figures are derived from census 2011. For 2016-17, the Gross Domestic Product (GDP) at ₹121,96,006 crore and per capita GDP at ₹93,888 by CSO indicates a population of

• 1,298,995,186 (or, 1.30 billion), perhaps for 31 March 2017.

UIDAI estimate

In addition to the above two estimates, the Unique Identity Authority of India (UIDAI), have also provided a projection of population for 2017 in an analysis of Aadhaar saturation. The note also indicates that  data for nine states/union territories (Andhra Pradesh, Chandigarh, Daman and Diu, Goa, Gujarat, Haryana, Himachal Pradesh, Punjab, and Uttar Pradesh) were provided by the respective states/union territories. It is not clear whether the independence to states was in estimating of population or for saturation analysis. In any case, the note does not delineate the method of estimating population, but as this is meant for an analysis of Aadhaar saturation in 2017, one expects that the estimate of population is likely to be for 31 December 2017. The UIDAI estimate for 2017 is

• 1,316,632,920 (or, 1.32 billion), perhaps for 31 December 2017.

UN estimate

Independent of the above three estimates, the United Nations led exercise of  World Population Prospects 2017 (also available at worldometers) estimates population for all countries from 1950 to 2100 with the reference date being the middle of the year, 1 July of each year. The UN estimate for 2017 for India is

• 1,339,180,127 (or, 1.34 billion), for 1 July 2017. 

Comparing four estimates

A cursory glance may suggest that the difference in population estimates may be because the reference dates are likely to be different. To address this, we take the estimates for 2017 and 2018 provided by the four different entities in Table 1 and one observes that the range of the estimates for two consecutive years by any entity (TGPP, GDP, UIDAI, and UN) does not overlap with the others.

Table 1: Population estimates for India in 2017 and 2018 through Different Entities
Years	TGPP	CSO	UIDAI	UN
2017	128,36,00,000	129,89,95,186	131,66,32,920	133,91,80,127
2018	129,80,41,000	131,59,94,518	133,56,10,549	135,40,51,854
Notes and Sources: TGPP-Technical Group on Population Projections 2006, CSO-Central Statistics Office (press note 2018, also see Handbook of Statistics on Indian Economy), UIDAI-Unique Identity Authority of India (projections for 2017 and 2018), and UN-United Nations (World Population Prospects 2017).

 

Policy pointers

Prima facie, one cannot reject the scientifically grounded UN estimates, unless substantive arguments are put forth. Besides, UN estimates, as is the practice, would have been developed with active engagement of officials and academia from all countries, including India. If there were any substantive differences then that ought to have been provided at that stage. If after that differences remain then they ought to be put up in the public domain.

It would help in provisioning of public policy if there is a common understanding to a basic matter like the total population of the country. This starting point will take us a long way in identifying sub-group consistent population estimates for different categories of vulnerable population and their geographical concentration or spread.

There should be serious efforts to provide population estimates for non-census years by taking into account the census of 2011. In today's age and computing advantages, even without the involvement and technological advantage of UIDAI, all this should be easily possible.

Way forward

The Office of the Registrar General under Ministry of Home Affairs, the Ministry of Health and Family Welfare, the Ministry of Statistics and Programme Implementation (including the Central Statistics Office) and all other entities should come together at the earliest to provide us with a subgroup consistent population estimates for non-census years. Till that happens, the UN estimates could be a starting point, the shares of population across states may be used from UIDAI or CSO estimates, and within states the sex ratio of TGPP estimates may be used to arrive at a gender-specific population estimate.