Evolving the kanban board

My wife and I are planning to move house. We aren’t sure where we want to move to, or indeed how much we have to spend. Naturally, though, we want to get the highest possible selling price for our current house in order that we have as many options as possible. So we called in a “house doctor” to help.

After she (the house doctor, not the wife) had recovered from the initial shock of seeing how we have customised a fairly standard 4-bedroom house into a 6-bedroom eclectic disaster, she produced a report containing a list of cosmetic improvements we should make in order to attract prospective buyers. The list is long, with jobs for myself, my wife, and our local handyman. We needed to make the project manageable in a way that would allow us all to contribute as and when we have the time. So I found an old whiteboard in the garage and made this:

full2

As you can see, I drew a very rough plan of the house, including sections for upstairs, downstairs, the attic, and the outside. We then wrote a small sticky note for every improvement suggested by the house doctor (blue) and some that we had always wanted to do ourselves (yellow).

When we finish a task, we simply remove the ticket. For example, you can see that we have already finished all of the tasks needed in the Office (priorities, right?).

up1

And why am I telling you all this? Because this is what I recommend teams do for their software projects. When you pick up the next feature, draw an architecture diagram and populate it with sticky notes. The resulting board is a “map” showing the feature and the tasks that need to be done in order to deliver that feature (thanks to Tooky for that analogy).

  • The diagram you draw for Feature A might differ from the one you draw for Feature B, because you might be touching different parts of your estate. That’s cool. The diagram needs to be the one that’s most appropriate for the work you’re about to do.
  • The visual representation of your architecture allows more people to be engaged in discovering the tasks that need to be done to deliver the feature.
  • And it allows everyone, often including non-programmers, to see and understand the scope and impact of what is to be done.
  • Sometimes doing a task will spawn others: things we didn’t consider when we did the original feature break-down; things we’ve learned by making changes or completing spike tasks; things we or the Product Owner couldn’t envisage sooner. That’s fine — we simply add and remove sticky notes as we think of them (and look for opportunities to slice off a separate feature that we can push back onto the ideas heap). The whole thing is quite dynamic, and yet very well controlled at the same time.
  • If possible I like to include testing in the scope of the stickies, possibly adding a few explicit testing task stickies where necessary.
  • As you finish each task (whatever “finish” means for your team), either remove the task’s sticky note or mark it with a big green tick. For our house doctor board, we’ve decided that removing the stickies is best. But for software teams, I generally recommend adding big green ticks to completed tasks. This allows anyone to see how much progress you have made through the current feature, and which areas still need more work.
  • Sometimes the distribution of ticked and un-ticked stickies will suggest opportunities for splitting the feature and releasing a subset earlier than planned.
  • Hold stand-up meetings around the diagram as often as you need, and certainly whenever anything significant changes. (Some of the teams I coach have been known to hold informal stand-ups 4-5 times each day.) The architecture diagram helps facilitate and focus these discussions, and makes it much easier for everyone to contribute.
  • Note that all of the above works best when the team has a single feature in flight. A WIP limit of one. Single piece flow.
  • This approach works well when combined with the 5-day challenge.

As usual with the recommendations I write in this blog, this idea is probably not a new one. But it is highly effective, and I recommend you try it.

Update:

I gave a lightning talk on this topic at the Lean Agile Manchester meetup this week. There is a video (below), although unfortunately you can’t actually see what’s on the slides. So I uploaded the slides here.

 

 

Where is the constraint in software development?

I just had a thought about the relationship between software development and the Theory of Constraints. It probably isn’t a new thought, although it seems to differ from some of the analyses I’ve seen elsewhere. Also, I probably won’t be able to express it in any coherent way; but here goes…

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Estimating user stories: the 5 day challenge

This is a quick note about an idea I’ve been using with a few software teams during the last couple of years. I also spoke about it briefly at the Scottish Ruby Conference this week (video at the bottom of this post). If you try it, please publish your experiences and link to them via the comments here.

TL;DR — don’t guess the size of a story; fit the story to the size you want.

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communicating intent is all about names

Ths ten-minute video chat between Corey Haines and J.B.Rainsberger introduced a nice simplification of eXtremeNormalForm.

In the discussion, JB hardens up the wishy-washy Communicates Intent value by noting that it’s just about “bad names”, and here’s why. In an OO language, “communicating intent” boils down to breaking the system into small pieces and giving them good names, names that resonate with the design and the domain. Small pieces are no good on their own, and good names for bad ideas will soon be weeded out. JB therefore claims that good design (he says good architecture) boils down to

  1. eliminate duplication
  2. eliminate bad names

(He takes passing all tests – ie. correctness – as a given, and he says that eliminating duplication and bad names also renders the software “small”. I disagree on that last point.) So, his assertion is equivalent to saying that every code smell is a symptom of either Duplication or Bad Names, which I find easier to explain than asking people to ensure that the code “communicates intent”.

iteration zero podcast

A couple of weeks ago Clarke Ching interviewed me as part of his Everyday Agile initiative. The discussion describes what happened when one of my clients, Codeweavers, invited me to participate in kicking off a new project. You can download the MP3 directly from here.

Warning: The sound quality and levels are very poor, because my headset had packed up. So we’ll probably be re-recording it (or something similar) soon.

In the meantime I’m interested to hear from you if you’ve done the same kind of exercise, and how it turned out.

why YAGNI acts to EXPLOIT the bottleneck

Clarke asked me to explain my earlier throw-away remark that YAGNI forms part of the EXPLOIT step in moving the bottleneck away from development, so here goes…

YAGNI (You Aren’t Gonna Need It) is an exhortation from the early days of XP. It has been discussed and misunderstood a great deal, so I’m not going to get into the finesses of meaning here. For our purposes, it reminds the developer not to work on features or generalisations that may be needed, telling him instead to focus his present efforts on delivering only what he knows is the current requirement. (In the interests of brevity, I’ll refer below to YAGNI only in terms of added behaviour, and I’ll use the word “feature” for any fragment of any kind of behaviour; all other forms of YAGNI are assumed.)

(In my practice I use a similarly attention-grabbing soundbite. Whenever I see a developer do something “because it may be needed in the future” I accuse him of crystal ball gazing. I remind the whole team that it can be risky and dangerous to get your balls out, and that seems to help the message stick. Other times there’s an embarrassed silence.)

Writing crystal ball code has three effects: In the present moment, it means that the developer is spending current time investing in one of many possible futures; in the period from now until that possible future, it means that there is code in the system that doesn’t need to be there; and when the future arrives, it may look different than that which the developer predicted.

First, then, crystal ball code uses up current development time. This is bad when development is the bottleneck and when batch sizes are relatively small and when development order has been defined in terms of business value and when feature cycle time is a KPI. The time spent developing a crystal ball feature will delay the current batch and all batches upto the imagined future. There is a tiny chance that development of that future batch will be faster (see below), but all interim ROI (for example) will be reduced by the delay introduced right now.

Second, the crystal ball code represents inventory, and it has a carrying cost. This code, which may never be required by the end user, must always build, integrate and pass all tests; if ever it doesn’t, time must be spent fixing it. Furthermore, a larger codebase will always require more time and effort to understand and navigate (think of having to drive around piles of inventory in order to fetch anything or the lean practice of 5S). Even if the guess turns out to be correct, the additional carrying cost of this inventory will slow down the development of all batches of features between now and the imagined future.

Third, the developer’s guess may be just plain wrong. Either the imagined “requirement” is never requested, or it is requested and by that time the codebase is radically different from what it is now. The developer may have to spend time removing the feature (for instance if it would confuse or endanger the user) or completely re-design it to make it match how reality turned out. It is assumed that the “wow, that’s exactly what we needed” outcome is sufficiently unlikely that the costs of the other outcomes dominate.

So YAGNI is based on a few core assumptions:

  • The product is to be built incrementally in batches of features
  • Each increment should be potentially shippable in terms of quality and cohesiveness
  • It is hard to predict what features will be requested in later batches
  • It is hard to predict what future code may look like
  • Development is the bottleneck
  • Speed of development is crucial
  • The present value of current features is higher than the future value of future features

Under these conditions, YAGNI is part of the EXPLOIT step because it helps to maximise the amount of current development effort going into delivering current value.

TOC and YAGNI

My apologies if this has been said or written a thousand times before: YAGNI is XP’s way of exploiting the constraint.

Which means that XP, and hence most agile methods, are set up on the assumption that the development team is – or soon will be – the bottleneck. And having identified that bottleneck, our first task is to EXPLOIT it – that is, we make sure that the bottleneck resource only works on stuff that contributes to overall throughput. YAGNI and test-driven development do that. Oh, and a relentless pursuit of quality, so that the bottleneck doesn’t have to spend time on rework. And effective communication, so we get to spend more time developing and less time writing documents and attending meetings. And tight feedback loops, so that we can identify which stuff is valuable and which isn’t.

Next we must SUBORDINATE the whole flow to the pace of the bottleneck. Fixed-length iterations help us to measure that pace, and the various forms of planning game and iteration commitment help to prevent work arriving too fast.

And only when all of that is working well is it safe to ELEVATE the constraint, perhaps by expanding the size of the team. I’m fairly sure I’ve never seen a real-life case in which this step was required. For most of my engagements, successfully exploiting the bottleneck caused the constraint to move elsewhere; and in the rest, the SUBORDINATE step revealed a deeper constraint elsewhere in the organisation.

hitting the high notes

In Hitting the High Notes Joel Spolsky makes a compelling argument in favour of hiring only the best programmers. I agree with his conclusion, if not with his supporting arguments.

Joel presents tables of data showing huge variation in the times taken by many students on a series of programming exercises. He then goes on to imply that this means there’s huge variation in these programmer’s talents in general, and that therefore one should seek to hire only the “best” if one wishes to be successful. My problem is that I find that to be a very narrow – and possibly short-sighted – definition of “best”. So one programmer can pass the professor’s unit tests four or six times more quickly than another. Does that mean the faster feller will be a constructive team member? Or a good designer? Or that his code is more adaptable in the long term? I do agree that there is huge variation among developers. And I do agree that a successful team must comprise “the best” almost exclusively. But a good team must also be a good mix, and “the best” must therefore be defined more broadly than in terms only of programming speed.

As a case in point, I’ve long been concerned about the “first” XP project, C3 at Chrysler. To many, the project’s success was a result of the strict adherence to being “extreme”. But I suspect that any project would be likely to succeed when the staff include Kent Beck, Ron Jeffries and Martin Fowler. The AgileNorth group have discussed this question many times without a conclusion: does the success of XP depend on the presence of highly gifted individuals, or can a team of average developers make it work? I believe the former to be true, and it may be true in general of any software project, XP or otherwise. Which I guess is the point that Joel is also making.

selling agile is not about programming techniques

We welcomed a couple of new faces to last night’s meeting of the AgileNorth group. Interestingly, both Josh and David want to get their work environments moving over to being agile, without either having tried it for real. So we spent a very pleasant evening out in the sun talking about how to sell agile into distinctly non-agile organisations.

One thing that struck me as fascinating: there seems to be a grand misconception that “being agile” is about TDD and pair programming. It isn’t – there’s far more to being agile than choosing the right programming techniques. Perhaps Kent Beck’s success in promoting XP has obscured part of the picture?

My own recent experience suggests that “XP” or “Scrum” or even “agile” isn’t the issue. As we discussed last evening, selling agile is really about delivering ROI quickly, incrementally and predictably. The techniques of XP will definitely help us turn the dials up to ten, but that’s rarely needed in the immediate term…