Innovation policy evaluation has been expanding over the past decades and now faces key challenges, some of which are methodological. In Europe, a particular aspect that poses difficulties to evaluators is the one of European Added Value (or EAV). In this book, Pierre Padilla and Geert Steurs explore the potential of Theory-Based Evaluation (TBE) for the evaluation of European Added Value (EAV) of Research, Technology Development and Innovation (RTDI) policies. The authors first identify key dimensions of EAV when applied to RTDI policy making. They then study two European policy measures in order to better understand the potential of TBE in practice. These two policy case studies are the SME-specific measures implemented under the Seventh Framework Programme for Research and Technology Development, and the Information and Communication Policy Support Programme (ICT-PSP) implemented under the Competitiveness and Innovation Programme. After in-depth analyses, the authors propose arefined approach of TBE, rooted into John Mayne's Contribution Analysis and applicable to other areas in which EAV is seen as a challenge for evaluators.