Maintain an approved dictionary showing each project, valid phase and cost code, plain-language definition, status, and responsible project owner. Include effective and closure dates so users do not keep posting to a completed job. If the accounting system supports valid combinations, document them; a cost code that is acceptable for one project may not be meaningful for another.
Avoid broad labels such as “other” unless the owner has defined when to use them. The review should not rely on a bookkeeper guessing from a short vendor description. Purchase orders, vendor bills, time records, expense reports, receiving records, and project instructions provide better evidence.