Allan Kelly blogged recently about whether kanban systems trade predictability for efficiency. Its an interesting viewpoint, but I’m not entirely sure I agree!
Firstly, I don’t believe any agile process gives predictability. One of the reasons for preferring agile methods is that software development just isn’t predictable. Rather, I would say that agile methods can give reliability and that both kanban and more traditional agile methods give equal reliability. Secondly, I prefer to focus on effectiveness rather than efficiency and that both agile and kanban value effectiveness over efficiency.
So, if there is a trade-off, it is between the amount of up front effort in planning in order to achieve reliability at the expense of effectiveness. Scrum (for example) invests time in Product Backlog and Sprint Backlog planning in order to communicate at a high level what should be delivered. Thus Scrum says “we believe we will deliver this much work over that time period, and that it will be made up those items”. Kanban, however, simply measures average lead time and due date performance. Thus Kanban says “we belive we will deliver this much work over that time period *but* we don’t yet know what those items will be – we’ll decide at the last responsible moment”.
Actually, I thinks its more a relationship between trust and effectiveness. The more mutual trust there is between the business and delivery team, the less up front planning is needed, and the more efficient a team can be. That’s not to say that Scrum has a heavy up front planning process, or is a low trust method, but Kanban takes advantage of more mutual trust in order to eliminate some overhead and be more effective.
Liz Keogh says “RIP As a… I want… So that…” (via David Anderson). This also ties in with what Chris Matts has being describing as Feature Injection. What I like about this idea is that it provides the link between the MMF and the User Story.
Liz proposes a new format:
- In order to <achieve some value>
- As a <role>
- I want <some feature>
The <some value> is a MMF – Minimal Marketable Feature. However, where minimal is still quite big, then MMFs can be broken down into <features>, which are more traditional User Stories. Thus the format gives a simple way of managing the relationship between the small incremental functionality pieces, and the larger value pieces.
Thanks Liz and Chris!
The final morning of the conference was faily quiet again. I did go to “The Agile Technique Hour” which was fun and interesting. David Parsons has posted the materials online, but in brief, we were split into teams in order to deliver features, which were drawings on functionality on overhead acetate. The features were integrated by overlaying the acetate sheats. Neat idea. Initially we had policies in place to inhibit productivity, and gradaully the policies were relaxed to allow us to collaborate better, refactor, regression test, continuously integrate etc.
What I found interesting was that our teams approach was to have a clear vision (a basic bicycle) and to focus on delivering the simplest ‘minimal’ solution for each ‘marketable feature’ and to focus on delivering the ‘minimal viable product’ e.g. the smallest set of features which gave a valuable useable product. In effect, we limited work in progress. We ended up completing nearly all the features without too much trouble (unlike the other team 😉 )
Here’s the final product:
An excellent workshop by Mary and Tom Poppendieck today entitled “Stop Thrashing: Pull Schedule Techniques for Level Workflow”. It really left me buzzing, for two reasons. Firstly, Mary talked about her real experiences implementing a kanban system at 3M which was fascinating, and secondly, I ended up being invited up to the front to share my experiences with implementing a kanban system at Yahoo!
Mary described how 3M moved from an MRP (Material Resource Planning) system which was software based and delivered 60% against plan, to a kanban system which was physical token based and delivered 95% against plan. The reason it worked was that ultimately, the system was designed by the floor workers who operated it – not by management – so when there were problem, the flow workers understand how to solve them. To quote Mary, “Computers destroy our capability to schedule”.
The key to a kanban system working is what Mary called ‘setup time’ – the time to get the system ready for production. A large setup time means that there need to be large batch sizes to be economically viable, whereas a small setup time means that batch sizes can be smaller. The smaller the batch size, the more just-in-time is possible, and the better the flow. Setup time for software is generally the merge/test/deploy process and this matched my experience. At Yahoo! we had a release cycle of one week, because that was how long the release setup time was. Reducing the time needed for the release process by employing more automation (e.g. testing) would have enebled us to release even more frequently. One of the goals for a lean manufacturing organisation is ‘single digit setup’, or a setup time of 9 minutes or less. Mary described a visit to a Toyota factory where the setup time was so small that they were able to achieve a batch size on one – each car in the line was different.
Mary also talked about Building the Empire State which was built in recored time (20 months from the start of the entire project) at a rate of one floor a day. The bottom floors were being built before the top had been designed by using a number of techniques:
- Collaborative teamwork between the owner, architects and builders
- Deigning such that construction was quick and easy (as opposed to cheap)
- Breaking dependencies so that elements of the building could happen in diffierent orders
- Focussing on the constraint to enable a flow of material
- Eliminating waste – for example having restuarants on the buildng during construction
In the afternoon I ran an OpenSpace session on kanban which had around 15 people come along to and I did a quick run through of my latest KFC slides. There seems to be a real growing interest in the community about these new ideas, and I think the explanations and understands are gradually becoming clearer.
Dave Snowden‘s keynote was entertaining and interesting, although quite a lot of it went over my head. Dave talked about the need to understand why something works in order for it to scale, with reference to agile development. His work covers Complex Adaptive Systems, Cognitive Systems and Evolutionary Phsycology and Anthropology.
Some points which stuck out for me were:
- Adopt a safe-fail experimentation rather than a fail-safe design approach
- Hindsight doesn’t lead to foresight
- Manage and monitor boundaries and attractors
- Measure impact, not outcome
I also attended Lasse Koskela‘s Retrospective Exploration Workshop. I was primarily interested in seeing how the exercises worked as I’m putting together our own similar course for Conchango as most of the content was based on the agile retropsectives bible. Unfortunately, there wasn’t really enough time for a good hands-on simulation, although it was enough to trigger some thoughts. One key thing is to have a shared context which participants to use. Another conundrum is whether to do lots of powerpoint up front, followed by a full retropsective simulation, or whether to interleave presentation with experience. One final nice idea which Lasse used was for situations where you don’t have much wall space. He lifted a table up onto its end, so the table top became a temporary wall which he could stick paper to.
Finally, Sean Hanly spoke about his experiences with a strartup TicketSolve. This was fairly standard stuff until he mentioned the magic work ‘kanban’! It turns out that they had difficulty in release planning due to the constantly changing priorities, so adopted a basic kanban approach whereby they only planned short term for the immediate customer needs, and pulled features in iteration by iteration. It sounded like they had lost some of the big picture as a result which a quarterly planning cadence could have helped with.
As usual side conversations have been as interesting as the main conference. A theme that has emereged for me is the shift from delivering ‘working’ software to delivering ‘successful’ software. That’s what Jeff Patton is aiming for, and I think its a goal of the KFC. Rather than simple asking ‘what do you want?’, ask ‘whats your goal?’ or even ‘what problem are you trying to solve?’. This helps focus on the value being developed and delivered.
I went to Jeff Patton‘s tutorial on User Story Mapping this afternoon. I first met Jeff in London last year at XP Day and the Scrum Gathering. We talked about kanban, and his ideas, and the two seemed very compatible, so I was keen to see how they matched in more detail. Jeff has also been working with former Yahoo! colleagues Joe Arnold and Aaron Sanders on a kanban related article, so he also sees a connection.
Jeff is trying to solve a number of problems with User Stories that I’ve also seen:
- they are difficult to prioritise because it is usually a collection of stories that provide value.
- it can be difficult to understand the dependenies between stories.
- it can be difficult to understand the whole system from a backlog of stories.
- creating more smaller stories makes the above even worse!
Jeff’s solution is to break a system down into the following hierarchy:
Goals -> Activities -> Tasks -> Tools
- Goals are the user centred things which are trying to be achieved
- Activities are role based themes of functionality
- Tasks are more specific, but still high level features, which make up an activity
- Tools are typical more detailed user stories
By creating this hierarchy and generating a physical map using index cards, the relationship between the various parts of the system, and the value that they are delivering, can be communicated and evolved. Activities form the ‘backbone’ of the system, and Tasks can be prioritised to form a ‘walking skeleton’, or a ‘fully formed, but immature’ system.
From a kanban perspective, it seems to me that the Tasks are similar to MMFs, and are what make up the kanban cards, and that the Story Map is a tool to inform both the value that they generate, and the order in which they should be scheduled.
I’m at XP2008 in Limerick this week. Today was pretty quiet as its all tutorials for the first couple of days, which cost extra, so I didn’t actually go to anything. However, I did hang around and catch up with some old friends.
In particular, I had an interesting chat with Tom Poppendieck about my experiences with kanban systems. Tom felt that while a kanban system was great for small pieces of work such as sustaining engineering, it wasn’t so suitable for larger pieces of work such as new product development. This is counter to my experience that a kanban system using larger MMFs as the kanban actually helps the focus on delivering value with a reduced cycle time.
While generally talking about Lean, Tom also recommended a new book, Ready, Set, Dominate: Implement Toyota’s Set-Based Learning for Developing Products and Nobody Can Catch You by Michael N. Kennedy, Kent Harmon. Another one to add to the reading list.
I’m really pleased to have had a number of submissions accepted for various conferences this year. I’ve added details onto my Calendar page.
In particular I’ve had 3 talks accepted for Agile2008 in Toronto, one of which is a workshop called KFC Development. I’m really looking forward to sharing my thoughts and getting feedback from attendees which I hope will help clarify the ideas.
I gave a short presentation at the Agile North April Mini Conference last Saturday. It was a great half day, and possibly the first Agile conference without any reference to Scrum or XP! Just Real Options and Kanban with Portia Tung, Pascal Van Cauwenbergh, David Anderson and myself.
I’ve added my slides to the downloads page. The talk was also videoed, so that may appear later aswell.
Unfortunately, we all had so much to say that we ran out of time, and I wasn’t able to play my “KFC Games”. Actually, they’re more simulations than games, but here’s some links to what they involve in case you want to try them out anyway.
I’ve been referring to my latest thinking on development process as KFC Development. Its a bit of a gimmicky name, which makes it memorable, but there is some meaning behind it. KFC stands for Kanban, Flow and Cadence – three lean concepts which I think are important and complementary.
Kanban – Kanban is the mechanism which controls the workflow and helps manage inventory and investment, and identify bottlenecks.
Flow – More specifically One Piece Flow. The one-piece is a Minimal Marketable Feature (MMF) which ensures there is focus on the delivery of actual value. This avoids the temptation to artificially break work down into smaller chunks in order to fit them it into an iteration or sprint. A side effect of this flow, is that typical agile time-boxed iterations can become unnecessary.
Cadence – Cadences give the team the rhythm usually provided by time-boxed iterations. There can be a variety of cadences, from daily stand-ups, to quarterly roadmap planning. An additional cadence is that defined by cycle-time, which determines throughput, and allows a level of forecasting of future work.
I’m hoping to explore these ideas more in the future.