Abstract

Like many countries, Ireland has been researching new systems of population
estimates compiled using administrative data. Ireland does not have a Central Population
Register from which the estimates can be compiled.
The primary step in compiling population estimates from administrative data is to first build
a Statistical Population Dataset (SPD). Ideally an SPD will have one record for each person
in the population containing the relevant attributes. The ideal SPD then allows compilation
of statistics by simply counting over records.
In practice, the compilation of SPDs is prone to error. These errors can be classified into 4
types of error; over coverage, under coverage, domain misclassification and linkage error.
Ireland, to date, has investigated 2 different approaches to the compilation of population
estimates from administrative data. The first, labeled in this paper as the simple count
method, is based on building an SPD which minimises the overall number of individual
record errors such that simple counts from the SPD will provide population estimates.
The second, labeled in this paper as the estimation method, is based on building an SPD
which aims to eliminate all error types bar that of undercoverage and then adjusts counts
for undercoverage using Dual System Estimation (DSE) methods to obtain population estimates.
This paper explores the advantages and disadvantages of both methods before considering
how they could be integrated to eliminate the disadvantages.
Many NSIs will be considering similar challenges when compiling annual Census like population
estimates and this paper aims to contribute to that discussion.