In this article, Mitch Lacey discusses the difficulty faced when trying to provide estimates for software development project. The beginning of a software project is the time when you are the least certain about the final scope project, but it is also when you are asked to deliver precise estimates. Agile tries to move from uncertainty to certainty in as quickly as possible.
The article presents two agile estimation techniques: planning poker and wall estimation. Planning poker is a good tool for estimating user stories, but it takes too much time to estimate hundreds of stories with this technique. Wall estimation allows stakeholders to prioritize a large group of stories without being trapped in discussions to decide if a particular story is slightly more important than another. Once the stories are grouped by size, customers and stakeholders can be involved to prioritize them. At the end of the sessions, your wall should break down roughly into four quadrants. The stories in the top left are high priority and small so they will end up in the top of the product backlog. The stories in the top right are high priority but are also large. These stories should be broken down soon so they can be brought into upcoming sprints. The lower left quadrant is made up of small stories that are lower in priority. They will likely fall to the bottom of the backlog. The lower right quadrant is filled with large stories that are also lower in priority. These stories are your epics or themes. They’ll eventually need to be broken down into smaller, more manageable stories but not until they rise in priority.