Trilhos - Desenvolvimento de competências pessoais e sociais. Reflex？es sobre a metodologia de avalia？？o

the article presents the program trilhos - developing personal and social skills and the discussion on the evaluation methodology. the trilhos is a comprehensive programme of prevention and intervention in the school setting within a 3 years period, considering 4 components: informative, decision-making and problem-solving, emotional regulation and communication skills. aims to reduce the number of students who start using tobacco, alcohol and cannabis before the age of 15. the authors present and discuss the results of the programme for a sample of 128 students from the 3rd cycle of studies, in a school from porto district. this article is a discussion on the procedures and evaluation methodology and about some of the constraints found.