Thursday, April 19, 2012

Points 4 of 4 - Breakdown

This entry directly continues from three earlier ones:
Duarte’s analysis, and my response, has got me thinking. And I think it would be useful - to me at least, maybe to some readers! - to explain why I think story points, or rather the “Abstract Points” that I prefer, are still useful, and why I advise teams to break down Blues - stories, possibly User Stories.

Why do I advise teams to break down Blues/Stories?

My background is as a C++ programmer, I worked on financial, telecom, and other systems. A business story, a Blue, would frequently be bigger than a developer could manage in an iteration - particularly if you have a legacy system. Thus I would break Blues down to Whites. (See Blue-White-Red (PDF) if you want to know more about this approach.)

Blues mean something to the business, Whites mean something to developers. I think this situation still holds for many developers in many environments. This has several advantages:
  • Whites are smaller pieces of work, they flow through a system more easily. Progress can be seen, tasks tracked, velocity calculated.
  • “The Business” aka Product Owner/Manager/BA are not always good at delivering small stories, breaking a blue down gives the developer a chance.
  • On some teams the business have been beaten up by development to request really small stories. However these stories lack business value. Because Blues are going to be broken down they can be large enough to have value even if that means that can’t be completed in one iteration/sprint.
  • (Yes, you heard that right) Whites are completed during the iteration, when all the Whites, or the essential ones, are completed then the Blue is completed.
  • Breaking Blues down to Whites is as much a design exercise as it is an estimation and scheduling one. This allows teams to engage in design and create a shared understanding.
  • Breaking Blues down to Whites frequently reveals functionality or assumptions about the Blue requirement which can be removed or postponed.
  • Having the Product Manager/Owner/BA in the room during this break down allows for requirements elaboration and knowledge mining.
  • Work can be rolled from one iteration to the next. I’m very relaxed about carry over work and I think for a new team its almost unavoidable. However doing it this way allows some points to be counted and illustrates what is happening.
(Of course the break down does create some problems: a Blue can only be done when all the Whites, or some done and other cancelled, which mean tracking becomes more complex. It might also break the Lean idea of “single piece flow” but I’m not sure.)

Next, why, given Duarte’s analysis, do I still advise teams to estimate their work?

  • I have seen the breakdown and estimate approach. As detailed previously in one case it allowed a team to forecast to the day.
  • Estimating work allows teams, and individual team members, to raise a warning when work is not understood, defined or involves a lot of risk. For example, a team estimating with planning poker will normally settle on an “average size” of task, e.g. 3 or 5 points. When they suddenly assign 13 or 20 points to a task something is wrong.
  • And just in case the warning is ignored the team, the people at the code face, the people doing the work, have a control mechanism. No matter how much the business or a manager bully a team they can still assign a high point score.
  • Equally, when differences in estimation appears it is a trigger to discussion, to learning, to understanding. This is desirable.
Finally, there is one more reason why I will continue to advise to point their work, and its one I don’t normally admit to but, well Vasco, you win.....

Placebo effect.

Managers, particularly trained project managers, find it alien to not estimate. Actually they are not alone, I’ve seen plenty of developers and testers who think the Kanban craze of not estimating work is nutty. Going through the rituals of pointing and planning poker provides at least the appearance of doing “the right thing.”

Asking these folk to go cold turkey on planning and estimation is tough.

Likewise, asking them to give up Gantt charts can be tough, so we offer them burn down charts. To be honest I find intra-sprint burn-down charts useless. Even the efficacy of pan-iteration burn-down charts surprised me at first. I now see they can be very useful and recommend their use. (Intellectually I prefer Cumulative Flow Diagrams but they are more difficult to get your head around and more difficult for the casual viewer to understand.)

A mature team is, almost by definition, beyond needing placebos. In a mature team I would expect the business to be requesting small stories which do represent value and do fit within an iteration. Thus I would expect Duarte’s analysis to hold up and a mature team might well decide to go without points and use cards.

However, for team at the beginning of its Agile journey I don’t expect these conditions hold.

Finally, for this instalment, I’ve started to wonder about Blue-White-Red again. I’ve long regarded Blue-White-Red as a Scrum/XP hybrid - closer to XP than Scrum if I’m honest. While I’ve been asked to write more about it in the past never have. Over time I have refined my thinking about it. I’m now wondering if Blue-White-Red is actually something more different than I’ve ever appreciated.

Maybe someone who has used Blue-White-Red can answer than one.

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