I recently wrote a post on Velocity Signature Analysis and have been looking at how undertaking large chunks of work as a complete team impacts velocity. We are currently three quarters of the way through a major (4 months long) piece of functionality and velocity is finally rising. This seems a pattern; for the early portion of a new area of work we spend a lot of time understanding the business domain and checking our interpretation using mock-ups and discussions. Velocity, in terms of functionality built and approved by the business is down during this time since many of the team members are involved in understanding the new business area rather than cranking out code.
As project manager I can get jittery, did we estimate this section of work correctly? Our average velocity for the last module was 60 points per month and now we are only getting 20! Weeks and weeks go by as whiteboards get filled, designs get changed, but the tested story counts hardly moves. Compounding this Discovery Drain phenomenon is the Clean-up Drain pattern. During the early portions of a new phase, fixing up the niggling issues hanging over from the last phase seems to take a long time. This makes perfect sense, if they were easy they would probably have been done earlier. It is always the difficult to reproduce bug, the change request that necessitates a rework of established workflow or multiple stakeholder collaboration that seem to bleed into the next development phase. While there may only be 3 or 4 bugs or change requests hanging over, they take a disproportionate amount of time to resolve.