This project developed an approach for eliciting the knowledge of threatened species experts in a structured way, so as to guide estimates of the benefits of alternative offset approaches. Although it doesn’t replace field-based studies, it can guide decision-makers in basing offset decisions on the best available information at the time, and help identify how much uncertainty there is about the effectiveness of particular offset actions. We tested the approach using several case study species that commonly trigger offset requirements, and for which developing appropriate offset proposals is considered challenging. Here, we describe the approach and findings for a suite of threatened reptiles that occur in the Brigalow Belt bioregion of eastern Australia.