Abstract
AIM: estimate the number of irregular economic immigrants in Mallorca. DESIGN: We used the capture-recapture method, an indirect method based on contrasts of data from two or more sources. Data were obtained from the Delegación de Gobierno (police and immigration authority), Comisiones Obreras (labor union), and institutions that provide health-related services to immigrants. Individuals were identified by birth date and country of origin. RESULTS: The total number of economic immigrants estimated with this method was 39 392. According to the Delegación de Gobierno data, the number of regular immigrants on the date of our inquiry was 9000. With the capture-recapture method, the number of irregular immigrants in Mallorca was therefore estimated at 30 000. CONCLUSIONS: The capture-recapture method can be useful to estimate the population of irregular immigrants in a given area at a given time, if sufficiently precise information on the identity of each individual can be obtained.