These agreements may take numerous forms, such as conditions on development permits, and mitigation bank instruments or other forms of landowner contracts, depending on the institutional arrangements on which the system relies (see also Chapter 3). Whatever form they take, offset agreements must be clearly defined, transparent and enforceable in order to provide a robust foundation for MRV and compliance at both the policy and the individual site level. Offset supply agreements may be based on the supply of inputs or outputs that lead to biodiversity outcomes or on the biodiversity outcomes themselves (Box 4.5). Such differences have driven many of the documented failures of offset projects in the past (Kenny, 2006). In the Biobanking scheme in New South Wales, Australia and the Native Vegetation Regulations in Victoria, Australia, offset supply agreements define regulatory compliance as the completion of pre-defined land management actions over time (DSE, 2012, NSW OEH, 2012).