The survey was carried out during the recruitment days in 2016 and 2017, which took place at the six CERECs of the Swiss Army. Conscripts are summoned for a period of two to three days. French-speaking conscripts go to Lausanne (Vaud), Italian-speaking conscripts to Monte Ceneri (Ticino) and German-speaking conscripts, depending on their canton of residence, to Mels (St. Gallen), Rüti (Zurich), Sumiswald (Bern) or Windisch (Aargau) (Office fédéral de la statistique, 2018).
In addition to the medical, psychological and sports examinations, the conscripts take part in the ch-x survey and fill in the survey together with other conscripts in a room at CEREC. The questionnaire is administered under the supervision of a ch-x expert who introduces the topic and the objectives.
In 2017, the Federal Office of Information Technology and Telecommunication (OFIT) has digitalized the paper questionnaires. The data they transmitted to the research team contained a total of 42,739 respondents
As with every ch-x survey, based on a stratified sampling strategy a comple-mentary sample of young Swiss women was selected. In addition to the five major cit-ies of Basel, Bern, Geneva, Lausanne and Zurich, around 100 municipalities were se-lected at random. Young women aged 18 to 19 were also randomly selected from these municipalities. The questionnaire was sent to them by post. A total of 2150 questionnaires were sent back to the research team.