Transition from initial education to employment has become more complex and protracted. Increasingly transitions are characterised by uncertainty and discontinuity. This can also be observed in countries with well-established vocational training systems. In Switzerland, policy makers ask for research which would provide them with basic information needed for educational planning. The research project TREE (Transition from Education to Employment) was launched in 2000. Its aim is to describe the post-compulsory educational and employment trajectories of youth and to analyse the main factors associated with linear resp. non-linear patterns of transition. TREE is designed as a PISA 2000 follow up survey. Up to 2007, seven yearly panels are planned. In the first two panels, more than 5000 young people from the German, French and Italian part of Switzerland took part. Results of the first two panels reveal that patterns of transition are strongly linked to socio-demographic factors of the surveyed people. Also, it can be shown that educational opportunities are strongly determined by the structures of the educational system. A highly selective educational system on lower secondary level considerably hampers access to upper secondary (vocational) education.Reviewing abstractDuring the last decades transition from education to employment has become more complex and protracted. Increasingly, transitions are found to be characterised by uncertainty and discontinuity. This can also be observed in countries with well-established and wide-spread vocational training systems, where links between the educational and the employment system are highly institutionalised. Recent studies on transitions from initial education to employment have found a great diversity of patterns of transition. It has been shown that patterns of transition are closely linked to educational and labour market structures as well as to individual and family characteristics (Furlong et al., 2002; Lamb, 2001; Scherer, 2001). In Switzerland, apprenticeship-based vocational education is the most important form of upper secondary education. Although compulsory education ends after 9 years of schooling, the importance of attaining an upper secondary certificate is stressed. Most young people who leave compulsory education seek access to the apprenticeship market. Up to recently, the direct and linear transition 'compulsory education - apprenticeship training - employment' has been the predominant policy paradigm. This traditional model was questioned when apprenticeship places were reduced in the early 90s. New training schemes had to be provided for those young people who had not found an apprenticeship place. Today, the traditional model of transition is questioned again by the findings of PISA 2000 (OECD Programme for International Student Assessment). According to PISA, 20% of the school-leavers in Switzerland don't have the knowledge and skills needed to enter any kind of VET. They are regarded as risk group, vulnerable to early dropout and non-completion of upper secondary programmes. Educational measures are called for to support those young people in their transition from education to employment. In order to find out more about the complexity of these transition patterns, the national research project TREE (Transition from Education to Employment) has been launched. The aim of TREE is to give a detailed description of educational and employment trajectories of youth upon completion of compulsory school and to analyse the main factors and characteristics associated with linear respectively non- linear flow patterns within and early drop out of upper secondary education.TREE is designed as a longitudinal study combining quantitative and qualitative methods. Taking the PISA 2000 survey as starting point, seven written surveys in the years 2001 to 2007 are planned. Each year, information is gathered on the educational process, progress and achievement of the surveyed individuals, the institutional context of their education or work as well as on psychological factors. In the first two waves, 5500 young people from the German, French and Italian part of Switzerland took part. In 2002, additional in- depth telephone interviews were carried out with those young people, whose transition had so far been non-linear or indirect.At ECER 2003 we would like to present results from the first two panels of TREE, linking the data gathered in 2001 and 2002 with data collected by PISA 2000. The presentation will focus on the patterns of transition which can be observed during the first two years after compulsory school. Typical patterns will be described and quantified. Then, it will be shown that certain patterns are strongly linked to socio-demographic factors of the surveyed people, such as their gender, their socio-economic and socio-cultural background or the language-region and urbanity of their place of residence. Finally, it will be argued that educational opportunities are strongly determined by the structures of the educational system. A highly selective educational system on lower secondary level considerably hampers access to upper secondary (vocational) education for youth, even if their PISA achievement scores are average or above.Furlong, A., Cartmel, F., Biggrt, A., Sweeting, H. & West, P. (2002). Youth transitions: patterns of vulnerability and processes of social inclusion. University of Glasgow.Lamb, S. & McKenzie, P. (2001). Patterns of success and failure in the transition from school to work in Australia. Longitudinal surveys of Australian youths, 18. Camberwell: ACER.Scherer, S. (2001). Early career patterns: a comparison of Great Britain and West Germany. European Sociological Review, 17, 119-144.