Whether the surveillance system produces the desired effect without wasting resources. Three levels of economic efficiency can be defined: - Optimisation: maximising the net benefit to society achieved by the allocation of scarce resources to animal health surveillance and intervention to avoid losses resulting from animal diseases - Acceptability: ensuring that the benefits generated by a mitigation policy at least cover its costs, this is commonly assessed using cost-benefit analysis - Cost-minimisation: ensuring that a technical target for disease mitigation (e.g. time to detection) is achieved at minimum cost without quantifying the benefit in monetary terms, this can be assessed using cost- effectiveness or least-cost analysis