"Transdisciplinarity, defined as the co-production of knowledge by scientists, decision-makers and other stakeholders, including lay stakeholders and communities, is also critical. Too often, urban policy is designed on the basis of scientific or political goals that do not take into account the perceived needs of the communities in which they are applied. No matter how valid, such actions are unsustainable, and the failure to consult can engender a lack of trust which hinders further efforts to resolve new issues. Just as important, local stakeholders have access to evidence and an understanding of local needs and processes that is otherwise inaccessible to researchers. Systems approaches ideally combine the expertise of scientists, the practicality of policy-makers and the local knowledge of communities to create feasible, actionable, valuable interventions. The City Blueprint methodology, for example, represents an effort to develop a comprehensive (interdisciplinary) set of indicators for urban water sustainability; in providing a simple but comprehensive baseline assessment for urban water cycle services, it represents a quick and transparent way to involve (transdisciplinary) stakeholders in understanding water systems and envisioning water services."