Main Article Content
After acknowledging the existence of different definitions of migrant, this work addresses the issue of achieving estimates that are comparable across time and space. Consequently, the first part of the work focusses on the definitions of migrant adopted by widely used statistical sources of migration data (ISTAT, UN, IOM, WORLD BANK, EUROSTAT). The second part critically analyses the migration data provided by ISTAT, EUROSTAT and UN, respectively referring to Italy, Europe and the world. As regards UN data on international migrations, the countries that define migrants by citizenship were kept separate from those that define them by place of birth. Finally, a comparison is offered between the data on immigration in Italy provided by UN (defined by place of birth) and those provided by ISTAT (defined by citizenship).