Decision models are becoming widespread in environmental management. They aid decision makers by enabling them to identify trade-offs and assumptions in the framing of problems – they do not make decisions. We presented a framework to examine allocation of resources between quarantine and surveillance, using Black rat invasion data on Barrow Island for illustration (Moore et al., 2010). In keeping with the philosophy of decision models as tools, we did not recommend resource allocation strategies on Barrow Island. Rather we demonstrated a rigorous approach to resource allocation, explored issues associated with management and identified areas for future work.