Excerpt from the original CRV Manual by Paul H. Smith:

For the sake of clarity, ease of instruction, and facility of control, RV methodology is divided into discreet, progressive “stages”, each dealing with different or more detailed aspects of the site. Stage I is the first and most general of the six stages thus far identified. Each stage is a natural progression, building on the information obtained during the previous stage. Each session must start with Stage I, progress on through Stage II, Stage III, and so forth, through the highest stage to be completed in that particular session.