V. Basili stated twenty years ago that a software organization that manages quality should have a corporate infrastructure that links together and transcends the single projects by capitalizing on successes and learning from failures. For critical systems design, the verification tasks play a crucial role; when an unexpected situation is detected, the engineer analyzes the cause, performing a diagnosis activity. To improve the quality of the design, diagnosis information have to be managed through a well-defined method and with a suitable system. In this paper we present how a Verification Organizing System together with a problem-oriented method could achieve these issues. The key aspect of the approach is to follow a step-wise building of the solution, reusing known problems that are relevant for the system under study.