Agile2011

In a complex environment, it can be impossible to write user-valued, end-to-end user stories that fit in a short sprint. In this talk, we'll understand the potential waste of trying to make stories _too_ small. I'll explain ways for teams to keep the value and fast feedback of short sprints without sacrificing the goal of having end-to-end user stories. Hint: you may have to set aside some of your Scrum dogma.
http://submit2011.agilealliance.org/files/session_pdfs/short sprint vs valuable stories.pdf