Although this study falls within the scope of migration statistics, the variables observed in the context of migration are based on the exchange between the place of birth and the usual residence (census time March 21, 2011). The 2011 Census, conducted by Statistics Portugal in cooperation with local authorities (municipalities and parish councils), was the only source of statistical information.
In general, with regard to studies on migration, we compared the population residence sites between two dates, usually with an annual or multiannual gap (example: five years). However, migration can also be observed over time. In this case, the analysis focused on the person whose place of birth is different from its usual residence i.e. a complete migrant according to the United Nations definition. Based on the individual questionnaire, the Census 2011 collected disaggregated information on individuals in the variables place of birth and place of usual residence, according to the Nomenclature of Territorial Units for Statistics (NUTS), at level II (region), level III (sub -region) and at the municipality level, making it possible to cross data by place of birth and by place of usual residence for the different territorial units.
The geographic diversity of the territorial units, regarding population attractiveness, is gauged according to the non-natural population of the municipality of residence (territorial unit which attracts population). The same method was used to measure the population repulsiveness (territorial unit that lose natural population in favor of others territorial units), which is the population living outside of the birth-municipality.

keywords: usual residence, place of birth, migration, demographic attractiveness, demographic repulsiveness