Population housing census support

Today, with major demographic shifts occurring and attention focused on international development, accurate and timely data are more important than ever. A census can represent a country, down to the smallest administrative unit, if conditions allow for it. Territories where a traditional census cannot be conducted countrywide due to inaccessible hard-to-reach areas, disasters or lack of infrastructure, modelled population estimates help to generate quality population data everywhere.


Population housing census

Afghanistan © UNFPA/Lorenzo Tugnoli

Why it matters

The information generated by a population and housing census – numbers of people, their distribution, their living conditions and other key data – is critical for development. Without accurate data, policymakers do not know where to invest and how to make the best, most informed decisions about development needs. Those most in need remain invisible. A census is among the most complex and massive peacetime exercises a nation undertakes. It does not merely count people but can also measure fertility, mortality and movement, helping to predict demographic trends. Census data can for example shine a light on inequalities in employment, education and wealth.

Our solution

A census provides population data down to the smallest statistical or administrative unit. With the support of UNFPA as the United Nations’ lead implementing agency, GRID3 contributes to the modernisation of census primarily through digital mapping, satellite imagery, and increased use of geospatial information systems (GIS) to improve accuracy, timeliness, quality, and use of census data. GRID3 also supports geospatial analyses of census data to identify populations in need. For countries conducting census activities in areas where enumerators cannot be deployed due to inaccessibility, disasters or insecurity, GRID3 can support modelling processes to estimate populations that otherwise would go uncounted.



“Within the GRID3 context, this entails support for digital mapping, use of satellite imagery and general increased use of GIS to improve quality of the census.”

Tapiwa Jhamba, Census Advisor, UNFPA

Modelled Population Estimates for Census Under-coverage

© UNFPA Viet Nam/Nguyen Thi Hong Thanh

Why it matters

Complete population numbers at all levels are fundamental for development applications, including the delivery and planning of services, election preparation and response to disasters. In less and least developed countries or hard-to-reach settings recent and reliable demographic data can often be lacking or incomplete. National population and housing census data can be outdated, inaccurate or missing key groups or areas that can’t be reached by traditional enumeration. Further, accurate boundary data are often limited, and high rates of migration and urban growth make existing data quickly outdated.

Our solution

Modelled population estimates go beyond the reach of traditional censuses by producing high-resolution estimates (100x100m grid cells) to address undercoverage in a traditional national census. Modelled population estimates rely on complete counts of population within small, defined areas, through ‘micro-census surveys’. Statistical models are then used to link these micro-census data to spatial data with full coverage over the regions of interest to predict population numbers in the unsampled locations. By aggregating these high-resolution predictions, population totals can be produced for administrative units or for the national and subnational level to produce the most complete censuses to date in countries where full coverage through traditional censuses is not possible. To find out more about the population estimates, please click here.



“There are places where census data cannot be collected due to conflict or security issues. The GRID3 programme provides the opportunity to estimate population using satellite imagery, micro-census data, and other geospatial data such building footprints to estimate the population at high-resolution levels and to fill in the data gaps of a census.”

Sainan Zhang, Technical Specialist, UNFPA

High-resolution population estimates

Mobility analysis

Mapping subnational boundaries

Settlement mapping

Infrastructure mapping

Capacity strengthening

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