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It’s Slack! Who Can’t See That?

Note: In his book “Actionable Agile Metrics for Predictability”, my colleague Dan Vacanti expands on my FedEx example while discussing further the notion and benefits of “slack” in the software development context. You’ll find this discussion in Ch. 13 Pull Policies.

“The beauty of using a flow system and a visual control is that we can measure cycle time and we can observe context…

The trappings of false certainty we gave ourselves in previous methodologies are being replaced with the comfort of graspable variation in kanban…

We now see knowledge work for what it is – a chaotic system that is fully manageable and understandable by its outputs and contexts, but very much unknowable by its actions and specifics.”

– Jim Benson, Sep 2011

The title of this post contains an answer and a question. However, it’s a “question” that prompted the answer part of this title, and my recollection of how both came to me originally, that I’m interested in sharing in this post and hope you find interesting if not amusing. As for providing an “answer” to the question part of this post’s title, that I’ll leave entirely to you.

Who Mentioned Variability?

This summer I had an opportunity to help out with a training class introducing the kanban method to a few members from several teams that all worked in software development and operations support context. On the second day of this training, we came to a section titled “Understanding Variability.” As the class began discussing why this might be important, I couldn’t help but flashback to a time when I heard my wife shout “It’s Slack! Who can’t see that?”, as she was watching a TV program in our family room. I’m sure at the moment of my flashback, more than a few in the training classroom wondered how I could be enjoying the discussion so much, while I sat there listening with a big smile on my face, chuckling a bit as if I was somewhere else hearing a comic telling his latest and greatest jokes. The truth was, I was somewhere else for the moment.

The year 2009 was coming to an end, and it was a few days before New Year’s Eve. I was at home in the loft sitting at my computer reading or writing something, when I heard my wife shout from below “It’s slack! Who can’t see that?” as she walked out of the family room. The tone in her voice hinted it was the “Who can’t see that?” part that she was most excited and proud to share right at that instant. However, I was much more interested in knowing the yet unknown question that prompted her to excitedly shout “It’s slack!” It was obvious too, she had more to share with me right then, something I’ll now share a bit about with you. (more…)

Basics of Reading Cumulative Flow Diagrams

Note: After reading this post, you may find these posts of interests as well:
Bottlenecks – Revisiting the Reading of Cumulative Flow Diagrams” dated 11/27/2012
Are You Just an Average CFD User?” dated 02/21/2014. Also, Dan Vacanti has also captured and expanded in greater detail on much of the topics touched on in this post, in his book titled “ActionableAgile.”

During our Agile Denver Kanban SIG’s September meeting, we revisited the previous month’s discussion on the “basics of reading cumulative flow diagrams.” I captured our initial questions and a brief summary of our discussion a few days later to post on our SIG’s LinkedIn site. However, I felt there was a bit more “food for thought” from our discussion to capture.

This post is the “expanded summary” inspired by our past two recent SIG meetings. If you’re relatively new to CFDs and still find the basics of reading them a bit puzzling, I hope these questions and the “walk-through style” responses help clear up a few things. If you see something that “smells” wrong or have an interesting insight, let me know that too!

First Things First!

If you’re completely new to CFDs, here are two links we used to “kick-off” our SIG’s discussions.

The first link is to a Slideshare post by Zsolt Fabok, on the basics of kanban. Check out slide 27 in particular though for a high-level visual and description of a CFD first.

The second link is to a blog post by Håkan Forss, where he does a great job showing step-by-step how to create a simple CFD using MS-Excel. This should help you get started creating your own but more importantly, even if you don’t create your own going forward, seeing and understanding the basic mechanics of creating one should help your understanding of them.

Wait, one quick question first, what is lead time, and what is cycle time, and how do they differ?