Page 298 - Invited Paper Session (IPS) - Volume 1

IPS153 John D.
1. Introduction
For countries that do not have a Central Population Register (CPR) on
which demographic statistics can be compiled, the production of coherent
statistics on population stocks and flows can prove challenging. This is
particularly true for those countries that have relatively high and variable
migration flows that are difficult to estimate.
The traditional approach to population estimates in these scenarios is an
application of the demographic component or cohort component method to
postcensal population estimates and then a recalibration of population
estimates for intercensal estimates. In a Eurostat review of 31 countries
(EUROSTAT, 2003) published in 2003, 19 countries were identified as using the
component method for population estimates. This approach can be labelled a
flows first based approach in that the population flows are first estimated and
then used to derive the stocks based estimate. The weakness with this approach
is that any errors or bias in estimating the components of population change
(births, deaths, immigration, emigration) will be carried forward from timepoint
to timepoint. These concerns, amplified in the presence of high migration flows,
are one of the reasons why some countries, such as Ireland, undertake a census
at 5 yearly intervals. The census provides a benchmark to recalibrate the
population estimates at regular intervals. In a subsequent review in 2015
(EUROSTAT, 2015), Eurostat found that 31 of 44 countries depended on the
census for annual population estimates and of these 31 countries only 9
supplemented their population estimates with information from registers.
For many countries, the census is the backbone to the system of
population estimates. Conducting a traditional census is a major logistical
exercise presenting many challenges, including those of cost, logistics and
timeliness. Given the associated challenges, these countries are seeking to
modernise and use administrative data as the basis of a modern system of
population statistics.
In the 2000 round of censuses only 4 of 44 countries conducted a register-
based census where the enumeration was based on a Central Population
Register (CPR) (UN-ECE, 2008). In a register based census persons and
households are simply counted using the CPR. The CPR, available in some
national administrations, is the backbone to the co-ordination and delivery of
public services to individuals and households.
The ability to compile reliable population estimates from administrative
data sources is a significant milestone in transitioning from a traditional
system of population statistics (with the traditional census at its core) to a
modern system of social statistics with administrative registers and
administrative data at its core. A modern system also holds the promise of
being able to conduct a census on an annual basis at a fraction of the cost of
what a traditional census would cost. Reliable annual population estimates

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