In cost accounting, an approach to group activity costs at the level of an organisation where they are incurred, or can be directly related to. Examples are the level where individual units are identified (unit-level), where batches of units are organised or processed (batch-level), where a process is operated or supported (process-level), or where costs cannot be objectively assigned to lower level activities or processes (facility-level). This approach is used to better understand the nature of the costs, including the level in the organisation at which they are incurred, the level to which they can be initially assigned (attached) and the degree to which they are assignable to other activity and/or cost object levels, i.e. activity or cost object cost, or sustaining costs.