Transformative Innovation Policy (TIP) is an emerging form for understanding and practicing innovation policy. It aims to mobilise innovation to tackle grand societal and environmental challenges as encapsulated in the Sustainable Development Goals (SDGs). TIP is an experimental approach that seeks to be inclusive, promote deep learning and, ultimately, achieve systemic change. These characteristics and the experimental nature of TIPs make them different from other approaches to innovation policy and require a different approach to evaluation. This brief proposes a formative approach to the evaluation of TIP experiments performed in protected technology niches, or policy experiments aimed at destabilising dominant, unsustainable socio-technical systems.