I keep hearing horror stories from managers about how their teams that have adopted Agile Development insist there are no documented requirements necessary when using the Scrum framework.This is wrong.  

Scrum is intentionally quiet about software requirements so that groups can use what works best for them.

In our training seminars, we show groups practicing Agile how they can benefit from a high-level "strategic" use case model.  This strategic model, or High Level Analysis, is used to flush out the users, the needs of the users, and to expose any data flow components. This technique has proved quick and effective.

Mike J. Berry www.RedRockResearch.com