Table 1.

Categories and definitions concerning migration in official statistics and in the KiGGS study

Source: own table

Category	Definition	Share of the population according to microcensus data 2020 [3]
Official statistics
People with migration background	‘Overall, the population with migration background is comprised of all people who themselves or at least one of their parents was born with a citizenship other than German. (…) This includes foreigners, (late) repatriates, naturalised people, and people who received German citizenship via adaptation, as well as the children born with German citizenship of these four groups.’ [4]*	27% (total population) 24% (adult population) 39% (population below 18 years of age)
Foreigners	‘Foreigners are persons who are not Germans in accordance with article 116 paragraph 1 of the Basic Constitutional Law. This includes stateless persons, as well as persons with unexplained citizenship. (…) They can either be born in Germany or immigrated.’ [4]*	12% (total population) 13% (adult population) 12% (population below 18 years of age)
People with own experience of migration	‘A person has their own experience of migration when s/he was born abroad. S/he is an immigrant.’ [4]*	17% (total population) 18% (adult population) 9% (population below 18 years of age)
Definition according to Robert Koch Institute, German Health Survey for Children and Adolescents (KiGGS)
Children and adolescents with migration background	‘Children who immigrated themselves from another country and who have at least one parent who was not born in Germany; or children whose both parents had immigrated or whose both parents do not have German citizenship.’ [5, p. 11]* ‘In the few cases where information on the country of birth of the child or on the birth countries/citizenship of the parents were lacking, the language spoken at home was used as an indicator for the migration background.’ [6, p. 14]*

^*represents our own translation