IMMIYEAR contains information on the year of immigration to Germany for all persons who have ever been a part of a SOEP household (i.e., the population from PPFAD, PPATH or PPATHL) and who were not born in Germany (see GERMBORN). The information on this variable was collected from the wave-specific individual questionnaires (dataset PL) or the variations of the “biography / life history” questionnaires (dataset BIOL) and from the additional questionnaire for 16-17-year-olds in use since 2000 (dataset JUGENDL). Since sample M (starting in 2013), information on all of a respondent’s stays in Germany has been collected (up to 15 moves between countries, see MIGSPELL and REFUGSPELL in the SOEP Survey Paper Series). For all cases in which a respondent had more than one stay in Germany, IMMIYEAR contains the respondent’s last year of immigration to Germany. In addition, information from the electronic household protocol for M1 or the retrospective survey of early childhood in the context of war and the post-war period (dataset BCBFK) was used (both datasets are not included in the standard data distribution).

When information in this working dataset consistently indicated a specific year of immigration, IMMIYEARINFO was coded “(1) consistent information” and the respective year of immigration was stated in IMMIYEAR. The vast majority of the persons who have ever been a part of a SOEP household (i.e., the population from PPFAD, PPATH or PPATHL) gave consistent information on their year of immigration. For another part of the dataset no direct information on the person’s year of immigration was available. “(3) No information” either refers to persons who lived in a SOEP household but did not complete an individual, life history, or youth questionnaire up to now or to respondents who were interviewed but did not answer the questions on their year of immigration. Over the course of the SOEP survey, only very few cases gave “(2) inconsistent information” with regard to their year of immigration. For these cases, their latest year of immigration was used in IMMIYEAR. The respondent’s year of birth was used as their year of immigration if they mentioned a year of immigration that was before their year of birth.

For those respondents who were not born in Germany and whose year of immigration could not be determined (IMMIYEARINFO value (3)), additional indicators were used to minimize the portion of missing values. These indicators were used in the following order (with descending priority):

1. When a respondent entered the SOEP for the first time because they had just moved into the household from abroad (see PZUG from PBRUTTO), the household entry year was considered to be the same as the immigration year.
2. Mother’s year of immigration was used as a proxy for the respondent when the respondent was born before the mother immigrated to Germany. If a mother’s year of immigration was missing, the father’s year of immigration was used to code IMMIYEAR. If a mother’s and father’s year of immigration were missing, the maternal and paternal grandparents’ year of immigration were used respectively.

If the year of immigration was still missing after this procedure, IMMIYEAR was coded “(-1) don’t know”. IMMIYEAR includes more missing values than GERMBORN and CORIGIN due to cases in which it was not possible to determine a respondent’s year of immigration. However, users should be aware that the wording of questions on the year of immigration vary rather drastically over the course of the SOEP survey (see Table 2). To provide the highest level of transparency possible, we include a variable for the quality of information used to create the year of immigration variable: IMMIYEARINFO.

Table 2: Variations of the SOEP questions regarding respondents’ year of immigration (main indicators for IMMIYEAR and IMMIYEARINFO)

Source: v35