This study investigates the possibilities of estimating value added as a performance indicator in senior secondary vocational education. Value added is interesting in this context because it is considered as a reliable tool for comparing the effectiveness of educational institutions. Although value added indicators have been developed since the 1980s for both primary and secondary educations, the research on school effectiveness has largely neglected vocational education because of its complexity. For estimating value added in this study, data concerning almost 90,000 students in Dutch senior secondary vocational education are used. Factors such as ethnicity, living in problematic neighbourhoods and students' prior educational attainment appear to be significant predictors of student outcomes. The results indicate considerable differences in the effectiveness among clusters of training programmes, whereas there are hardly any differences between the educational institutions. Of the total variance among the student outcomes, 14% is related to the training programme clusters. (Contains 3 tables and 3 figures.)