The dual system of vocational training, utilising both company training and vocational school attendance, is generally acknowledged to be a successful model for reducing youth unemployment. However, the decreasing number of training opportunities in countries with this system poses a crisis for the approach. One strategy for overcoming the problem involves offering incentives for companies to create new take-ups. The present study explores the necessary conditions for successfully influencing the number of training places through apprenticeship marketing. It does so following the realistic evaluation approach. A comparison of qualitative case studies of six projects demonstrates that context, in the sense of basic structural conditions and political sensibility, plays a role in the success of a project. However, even more important is the form of the project itself. This regards the behaviour of the actors involved (politics) as well as the choice of the measures (policy) and project organisation (polity). The study stresses the combined effects of these factors.