A preliminary research carried out in 2003 entitled Effective Violence Prevention and Intervention among Children and Adolescents in Zurich had the aim of providing support to the authorities of the City of Zurich Council in choosing appropriate prevention programmes. The study researched the existing prevention and intervention structures and developed recommendations for effective prevention programmes.
The collaboration between the City Authorities and the research team led to the creation of the Zurich Intervention and Prevention Project at Schools (zipps) in 2004, entailing two complementing projects. One of these were two prevention programmes - Triple Pand PATHS - were implemented in randomly selected primary schools in the context of the Zurich Programme for the Promotion of Social Skills in Schools (z-ok). The programme management and financing was coordinated by the School and Sport Department of the City of Zurich Council. The Zurich Project on the Social Development from Childhood to Adulthood (z-proso) continuously measures the effectiveness of the two intervention programmes and on a broader scale the social development from childhood to adolescence and adulthood.
The target population of the research is children who started first grade of public primary school in the City of Zurich in 2004. The sampling and the allocation to the different treatment conditions were carried out at school level. Out of a sampling frame of all primary schools, 56 primary schools with 113 first grade classes were randomly selected by means of a stratified sampling procedure. Fourteen schools were allocated to each of the 4 treatment conditions: "control group"; "PATHS-group"; "TripleP-group"; ant the combined "PATHS/TripleP-group".
1'675 children entered first grade in the selected schools in autumn 2004. Parents of 1'366 children (82 %) allowed the participation of their child in the surveys. 1'240 mothers and fathers (74 %) agreed to participate in the surveys themselves.
In the 9th grade, when the participating young people could decide on their participation themselves, the highest participation rate was recorded with 1'446 participants (86 %). In the most recent survey, at the age of 24, 1'160 people still took part.
These high participation and retention rates, as well as the multicultural sampling and the study duration of almost 20 years, distinguish z-proso as a research dataset of inestimable value, also in international comparison, from which more than 120 articles have already been published in renowned scientific journals.