Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Estimation of the number of irregular foreigners in Poland using
  non-linear count regression models   Population size estimation requires access to unit-level data in order to
correctly apply capture-recapture methods. Unfortunately, for reasons of
confidentiality access to such data may be limited. To overcome this issue we
apply and extend the hierarchical Poisson-Gamma model proposed by Zhang (2008),
which initially was used to estimate the number of irregular foreigners in
Norway.
  The model is an alternative to the current capture-recapture approach as it
does not require linking multiple sources and is solely based on aggregated
administrative data that include (1) the number of apprehended irregular
foreigners, (2) the number of foreigners who faced criminal charges and (3) the
number of foreigners registered in the central population register. The model
explicitly assumes a relationship between the unauthorized and registered
population, which is motivated by the interconnection between these two groups.
This makes the estimation conditionally dependent on the size of regular
population, provides interpretation with analogy to registered population and
makes the estimated parameter more stable over time.
  In this paper, we modify the original idea to allow for covariates and
flexible count distributions in order to estimate the number of irregular
foreigners in Poland in 2019. We also propose a parametric bootstrap for
estimating standard errors of estimates. Based on the extended model we
conclude that in as of 31.03.2019 and 30.09.2019 around 15,000 and 20,000
foreigners and were residing in Poland without valid permits. This means that
those apprehended by the Polish Border Guard account for around 15-20% of the
total.

12
The categories of this paper are: nucl-th
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph