One of the ways in which planning authorities can ensure developers are doing the best they can for biodiversity is by examining their understanding of the Mitigation Hierarchy. Described by CIEEM (the Chartered Institute of Ecology and Environmental Management) as “the cornerstone of achieving BNG”, the hierarchy is a linear process; a sequential set of steps from best scenario to worst scenario, namely (1) Avoid, (2) Minimise, (3) Compensate, (4) Enhance.