Abstract. The aim of this paper is to propose the main elements of a theoretical and methodological framework for the assessment of the success of complex policy mixes, to highlight the conflicts between individual instruments and other elements within those mixes and to propose policy recommendations in order to mitigate them. Some criteria are defined, and different levels of analysis are considered. The challenges in evaluating policy packages are illustrated with the case of the coexistence between renewable energy support and emissions trading schemes. It is shown that policy mixes inherently lead to interactions between the different instruments, either in the form of conflicts or synergies. Conflicts are horizontal (i.e., between different types of instruments) and/or vertical (i.e., between different administrative levels). It is suggested that mitigating those conflicts could require administrative coordination. Relevant coordination could take place between different administrative levels and relate to different instruments or different design elements within similar instruments. However, given the trade-offs between different criteria, the role of coordination is necessarily limited.