Saturday, March 22, 2014

Estimation as a requirements Exercise

I explored the role of estimation in a couple of articles on Techwell recently.

In the first article I discussed how teams balance the cost of estimation (in terms of time it takes) with the value it brings to the project. Some argue that estimation isn't very useful at all, where other's say that it can be useful, but that all stakeholders may not have the same vision of the value estimation brings.

In a follow up article I explore the debate about whether to estimate in hours, which reflects effort, and time, or  points, which reflect complexity. This is a common debate, since many articles on agile advocate points, to step away from the concepts of estimate, and focus on the complexity of a feature, and also to help teams move towards the model of the estimate being valid for the team and not just a particular person. And stakeholders are often concerned about schedule and deadlines, so tend to prefer hours initially.

Different teams will come to different decisions about what works best for them. To me the most important part of the estimation discussion is the part many teams don't have, namely asking (and answering) the question of why they are estimating, and what value the estimates bring to the project given that they are now working with an agile process.

As I think more about what value estimation has brought to teams that I have worked on, I realize that the biggest value is that of having a a discussion of scope. When you have an planning meeting, a few questions come up:


  • Why people have different estimates
  • Why the estimate is larger, or smaller, than the product owner expected
  • Whether the team really understands what the story means.
Give this I'm leaning towards thinking of estimation as being more about requirements definition rather velocity, effort, or even complexity.  To that end, maybe the approach to use is one where you spend all of your planning effort defining stories in terms of small, fixed size units, and your velocity is about how many stories you finish off of a prioritized backlog. I link to a description of what this means in the points and hours article.

I'm  interested in hearing about creative approaches your teams have used for estimation. Please comment on  the Techwell articles, or here if you want to share lessons you have learned.