This guideline establishes the basic principles of codes of accounts (COA) for projects in any industry. It examines key characteristics including usage, content, structure and format and describes benefits of establishing standard COAs. Topics such as activity-based costing and work breakdown structures as they relate to COAs are addressed. The issues of properly defining a WBS and how it should be structured are outside the scope of this guideline. COAs are applicable to all phases of the asset life cycle, however, this guideline specifically addresses the project execution phases of asset design development through to start of normal operation.

A project code of accounts is a coded index of project cost, resource and activity categories. A complete COA includes definitions of the content of each account code and is methodically structured to facilitate finding, sorting, compiling, summarizing, defining and otherwise managing information the code is linked to. The information is used to support total cost management practices such as cost estimating, cost accounting, cost reporting, cost control, planning and scheduling. Other names used for COAs are coding matrices, coding structures, charge accounts, asset or material classification accounts, value categories, cost elements, work breakdown structures, resource breakdown structures and activity breakdown structures.