Estimation of fertility in Poland and of Polish born women in the United Kingdom

The aim of research presented in the paper is to explore the comparison of Total Fertility Rates of Polish women in England and Wales, with the rates for Polish women who are residents in Poland. Population censuses in Poland and the United Kingdom in 2011 provide information for such comparisons and show higher fertility rates of Polish women abroad than in Poland. Two specific questions were investigated. The first one is the question of the number of children born in Poland. It was observed that the number estimated on the basis of census data was not consistent with birth records in the register. The second question concerns the number of the usually resident population in Poland. We provide quality assessment of 2011 population census in Poland, estimates of actual and usually resident population. Based on thorough evaluation, a correction of the population estimates is proposed (RAF). Due to non-response and data omissions, the idea of Small Domain Estimation is applied with two a priori age and sex distributions: from the Polish Census Survey and upon the UK census. Fertility in Poland is estimated with regard to usually resident population published on the Census Hub, our RAF estimates and LFS data. The estimates of women at reproductive age differ for over 495,000, what cause certain discrepancies in TFR. Additionally we analyse changes in timing of birth and provide tempo adjusted TFR. The paper shows consequences of population estimates for measuring fertility. It was found that depending on the population estimates TFR in Poland differs from 1.31 for actual population to 1.45 for RAF estimates and 1.63 for tempo-adjusted TFR. Via detailed empirical examination of the usually resident population estimates in Poland we show inconsistencies resulting from the flexibility in interpretation of definitions given by EU 1260/2013 and specific regulations of individual countries.