Some people want to take the stance that no work should be done in advance of the sprint. That is clearly untenable. To see why, let’s take that view to its extreme: If we did nothing in advance to understand what we’re building, we’d show up at the planning meeting and say, “Hey, what should we build this sprint? We were working on an eCommerce site yesterday, but I think maybe we should switch to writing a word processor…” The team would literally have nothing written down—no product backlog / user stories / prioritized feature list at all.
The article “<a href=”http://www.mountaingoatsoftware.com/system/article/file/12/UpsideOfDownsizing.pdf”>The Upside of Downsizing</a>” describes how a project was successfully downsized from 100 to 12 developers. To make such a dramatic adjustment the development process was switched to Scrum and user stories.