The statement that best describes iteration and the ADM is that the ADM is iterative, over the whole process, between phases, and within phases4. Iteration is a key concept in managing the complexity of developing an Enterprise Architecture and managing its lifecycle4. The ADM supports several forms of iteration as follows:
* Iteration over the whole process: Projects will iterate through the entire ADM cycle, commencing with Phase A (Architecture Vision) and ending with Phase H (Architecture Change Management)4. Each cycle of the ADM will be bound by a Request for Architecture Work that defines the scope and objectives of the project4. The architecture output will populate or update the Architecture Landscape that describes the current and target states of the enterprise4.
* Iteration between phases: Projects may cycle between ADM phases in planned cycles covering multiple phases4. Typically, this is used to converge on a detailed Target Architecture when higher-level architecture does not exist to provide context and constraint4. For example, a project may iterate between Phase B (Business Architecture), Phase C (Information Systems Architectures), and Phase D (Technology Architecture) until a satisfactory solution is achieved4.
* Iteration within phases: Projects may return to previous activities within an ADM phase in order to circle back and update work products with new information4. Typically, this is used to manage the inter- relationship between different aspects of an architecture domain or viewpoint4. For example, a project may revisit Business Architecture models after developing Information Systems Architecture models to ensure alignment and consistency4.