Wednesday, December 1, 2010

When average is good

Calling something average is one step removed from calling it mediocre. But in the mathematical sense, especially when applied to a team’s velocity it’s a good thing.

One of the certain tricky bits for any new team trying out scrum is establishing the team’s capacity. That is, without an historic record of how many story points of work a team can complete you are somewhat in the dark as to what to aim for come sprint one.

For a team that’s been working together in the past but not estimating in points it’s possible they may have a fairly accurate gut feel for things, and that can be your guide. There’s likely still the novelty of having not just to develop but also test, fix defects and truly complete (according to your definition of done) but, with experience of working together in the past a decent guess can be made.

For a newly assembled team however, or one that’s less confident in figuring out how much of the backlog to bite off initially, my advice would simply be don’t worry. Just pick more than enough and accept that you won’t make it all. From what I’ve seen the first few sprints are very much a learning experience and part of that learning is going to include figuring out your capacity.

Given just three or four sprints the team, with good coaching and guidance from a competent scrum master, will have figured out a number of recurring key items: big stories are bad, transparency between those that code and those that test is key, getting things “done” means limiting how much you work on concurrently and, ultimately, a reasonable average velocity to work with for planning future sprints.

The team I am currently working with had quite an erratic velocity initially: 16, 8, 49 (yes really!) and then 26 points. After this we have stabilized nicely with an average of 24 points a sprint.

This “we dunno, we’re just gonna try it and see” approach to working out a team’s capacity for quality work is inarguably logical. However it doesn’t necessarily sit well with those from a command and control background, especially those with management responsibilities for the team new to scrum. They like detailed planning. Predictability. Commitments. Maybe even punitive action against teams that “fail”.

This is completely the wrong approach.

Like it or not, this is when managers need to decide if they are truly supporting scrum or not. If you are, then step up. Provide the environment your team needs in this early phase of the adoption. Make them comfortable with the new regime of trying, reflecting, learning and improving. Without that support you will stifle their ability to rapidly improve, and in turn lead to a less than stellar scrum implementation. Maybe even to a failed one. This happens a lot, and people revert to traditional, comfortable but ultimately unsatisfactory approaches to building software. Don’t let this happen to your team. Create the right environment and harness the power of average.

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