Most studies which have an impact start with a sort of re-examination stage, Techniques of Systems Analysis notes, where they investigate the current prejudices and concepts:
It often turns out that a system designed for perfectly sound historical reasons is no longer effective because conditions have changed. However, the historical reasons for designing the system are embodied in the planning factors and tactics used in official studies. Therefore, the first job of the analyst is to get a reasonably accurate idea of what the facts really are. These cannot be obtained solely from official sources because it should be one of the major purposes of the study to review these numbers. It is also important for the study to generate on its own the numbers which previously have been ignored or treated in an offhand way.