  In this article we describe a study aimed at estimating job vacancy
statistics, in particular the number of entities with at least one vacancy. To
achieve this goal, we propose an alternative approach to the methodology
exploiting survey data, which is based solely on data from administrative
registers and online sources and relies on dual system estimation (DSE).
  As these sources do not cover the whole reference population and the number
of units appearing in all datasets is small, we have developed a DSE approach
for negatively dependent sources based on a recent work by Chatterjee and
Bhuyan (2020). To achieve the main goal we conducted a thorough data cleaning
procedure in order to remove out-of-scope units, identify entities from the
target population, and link them by identifiers to minimize linkage errors. We
verified the effectiveness and sensitivity of the proposed estimator in
simulation studies.
  From a practical point of view, our results show that the current vacancy
survey in Poland underestimates the number of entities with at least one
vacancy by about 10-15%. The main reasons for this discrepancy are non-sampling
errors due to non-response and under-reporting, which is identified by
comparing survey data with administrative data.
