During World War II some 70,000 children were evacuated from Finland to Scandinavia, mainly to Sweden and placed into temporary foster care. The aim of the study is to evaluate the long-term consequences of the evacuation of Finnish children to Sweden during 1939-1945. The objective is to analyze the effects of breeding environment (nurture effects) on later life outcomes such as educational attainment, risk behaviour, mental and physical health and mortality exploiting the intervention into childrens’ early life family environment and quasi-random assignment of foster families. The focus is on the experience of the child and on the effect of the evacuation on the evacuees’ psychosocial well-being.The study is an inter-disciplinary, multicenter study. The study makes use of a natural experiment on Finnish war time evacuees who were brought to Sweden and sorted in an arguably haphazard fashion to host families in Sweden. The Principal Investigator of the project is docent Nina Santavirta and the project is affiliated to the Institute of Behavioural Sciences, University of Helsinki. Researchers affiliated to other organisations and departments and participating in the project and using the data sets of the project are: Department of Developmental Psychology, Faculty of Social Sciences, Åbo Akademi University, Department of History, Faculty of Arts, University of Helsinki, Swedish Institute for Social Research, Stockholm University.The research tasks of the study are: (1) To historically uncover the evacuation event (2) To analyze the effects of forced migration on cognitive skill formation (language acquisition, education, SES); on mental health (resilience, morbidity and mortality); (3) To determine risk factors for the war childrens’ health and psychological well-being (4) To identify factors that moderate and mediate physical and mental health in the life span of evacuees (5) To deepen the understanding of how the evacuation has influenced on a) the development of the self-image and identity of the evacuees and b) on attachment patterns in generational transmission. In the project several types of data have been analyzed: survey data, qualitative, interview based data and register based data. A deductive approach applying modern statistical methods as well as an inductive approach with qualitative data analyses has been applied. The project was supported by The Finnish Academy and The Signe and Ane Gyllenberg Foundation and the Wilhelm and Else Stockmann Foundation Stockmann Foundation (main supporters).