Gap Analysis in TOGAF is a technique used to compare the baseline architecture (current state) with the target architecture (future desired state). The output is a set of gaps, representing what is missing or what must change to move from baseline to target. These gaps help validate that the target architecture is adequate: by identifying what is not addressed, architects can ensure that all required functionality, constraints, and transformation paths are captured. In effect, Gap Analysis validates the architecture by exposing omissions, inconsistencies, or unmet requirements between what is and what should be. It is not primarily about defining service levels, nonfunctional requirements, or quality metrics (though it helps inform those). Rather, its main role is in validating and guiding closure of architectural gaps.