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Survey Design

COCON is a comparative longitudinal study that examines three age groups at three prototypical stages of growing up: 6 year-olds (mid-childhood), 15 year-olds (mid-adolescence) and 21 year-olds (late youth or early adulthood).

The most important caregivers for the 6- and 15-year-olds were also included in the survey; the parent who does the most supervision and spends the most time with the child (principal caregiver) as well as the most important instructor, such as the kindergarten teacher or main class teacher.

The two younger cohorts were interviewed every three years within the framework of the representative longitudinal study. Additionally, further survey data was collected both shortly before and after important transitions, such as school entry or the start of an apprenticeship. This takes into consideration that not necessarily all children and adolescents of the same age undergo important transitions at the same time.

Cocon Diagramm

COCON consists of both a representative and an intensive study. The representative part includes about 3,000 children, adolescents and young adults, who give interviews on a wide range of topics. The intensive study is conceptualised as a supplement to the representative study for the 6 year-olds and is carried out with 175 additional children. It focuses on topics regarding developmental psychology and aims to investigate specific aspects in more depth, such as moral development in mid-childhood. Thereby important instruments of measurement can be validated in the representative study. For psychological questions, these are usually in the form of extensive scales, which could not be used in the wider representative study for methodological and practical reasons. On the other hand, the psychological development side of COCON can be extended.


In the representative study, a two-step process was used for sampling. In the first step, municipalities were chosen. In the second step, children, adolescents and young adults in the chosen age groups were taken from the corresponding resident registers. This two-step process was also used for the sampling in the intensive study, whereby the choice of municipalities was not carried out according to representative criteria.