How many immigrants live in Spain? An alternative estimation to the population register based on births and fertility rates

Luis Rosero-Bixby, Universidad de Costa Rica
Teresa Castro Martin, Spanish National Research Council (CSIC)
David Reher, Universidad Complutense de Madrid
María Isabel Sánchez-Domínguez, University Complutense of Madrid

Estimates of international migration are subject to controversy everywhere. We use indirect methods to validate existing estimates of the number of immigrants from Spain’s municipal population registers (padrón). These registers might be over-counting immigrants who double register in different municipalities or fail to deregister when leaving the country. The proposed method uses two pieces of information: births to immigrants and their fertility rates. Data on births by parent’s nationality come from the Spanish national registry; fertility rates are estimated with data from the National Immigrant Survey (2007). Our estimates resulted in lower numbers of inmigrants than the 2005 padrón. However, the difference for females was small and within sampling errors. The difference for males is larger and significant, but uncertainties regarding male fertility cast doubts about it. We thus conclude that there is no enough evidence of significant overcount in the Spanish padrón of immigrants.