Final answer:
Earned value credit for materials, equipment, and purchased services in project management is taken when the related work is performed or items are delivered and accepted, complying with cost accounting principles.
Step-by-step explanation:
When considering earned value management (EVM) in project management, earned value credit for materials, equipment, and purchased services is typically taken at the point when the value is actually earned, which means when the work is performed or the materials and services are delivered and accepted by the project. It is important to align this with the project's cost accounting practices, where costs are recognized in accordance with the accrual accounting principles and contributions to the project objectives. The Physical Percent Complete method is often used for taking earned value credit for materials and equipment, where the credit is given based on the percentage of the work that has been completed.