The baseline investigation involves a postal questionnaire regarding socioeconomic position (SEP), health, health behaviors, material factors, psychosocial factors, youth circumstances and sociodemographics.

Information from the baseline postal survey onward has been linked to three main databases: the Cause-specific death registers from Statistics Netherlands; the National Medical Register including hospital admission information from all Dutch individuals; and the Regional Cancer Surveillance South.

Two subsamples (random sample and chronically ill sample) were invited to participated in additional in-depth interviews. They answered questions about socioeconomic position (SEP), SEP-related information, health, health behaviors, psychosocial factors, cultural factors, youth circumstances and sociodemographics that were not addressed in the postal survey.