It is widely considered that, in regions with significant geologic complexity, methods which work directly in the depth domain are superior to methods which operate on prestack time data. So, for example, velocity analysis using depth migration and residual moveout became standard in the industry. The most common depth-velocity analysis attempts to flatten common-image-migrated gathers for main reflectors by measuring depth errors as a function of the offset. At the same time, the fact that most depth-domain algorithms are valid only for correct or nearly correct velocity models should not be underestimated. If this assumption is violated, they can lose their convergence properties or produce wrong results.