Select Page

Bottlenecks – Revisiting the Reading of Cumulative Flow Diagrams

“Queues lie at the root of a large number of product development problems. They increase variability, risk, and cycle time. They decrease efficiency, quality, and motivation.”

“Large queues form when processes with variability are operated at high levels of capacity utilization. In reality, the misguided pursuit of efficiency creates enormous costs in the unmeasured invisible portion of the product development process, its queues.”

“Since high capacity utilization simultaneously raises efficiency and increases the cost of delay, we need to look at the combined impact of these two factors.”

“We have already pointed out that companies do not manage product development queues. What do they manage? Timelines...In contrast, when we emphasize flow, we focus on queues rather than timelines. Queues are a far better control variable than cycle time because, as you shall see, queues are leading indicators of future cycle-time problems. By controlling queue size, we automatically achieve control over timelines.”

– Don Reinertsen, 2009 – The Principle of Product Development Flow: Second Generation Lean Product Development

If you’re new to or rusty on CFDs, it would be helpful to review “Basics of Reading Cumulative Flow Diagrams” first. This earlier post covers basic definitions and the mechanics of reading WIP (work-in-progress), lead-time, and an average completion rate (throughput) from a CFD. It also includes links to external sources, one showing a basic example of how to create a CFD using MS-Excel, and another providing a quick overview of their use in the kanban method context. From this foundation I’d like to shift here toward a visual analysis perspective, exploring a few contexts where a bottleneck in our workflow is more or less present and see how it might appear on a CFD.

To be clear, I don’t think CFDs are the only way or “a best way” for spotting a bottleneck in your workflow. If you’re adequately visualizing your workflow on a board and diligently measuring and managing work items as they flow through your process, you’re well on the way to being able to identify where any bottleneck might be occurring. (Note: see my Kanban Board Design Primer under Resources/Nuggets here). That said, don’t under-estimate the value of using the CFD as well for learning about what happened, is happening, or will happen in your workflow. It can be a very effective tool for creating an easily accessible visual historical record and a trending perspective of a workflow in your context.

What is a Bottleneck?

Let us get a shared understanding of the term “bottleneck” by first looking at these selected Wikipedia definitions:

  • Metaphorically a bottleneck is a section of a route with a carrying capacity substantially below that characterizing other sections of the same route. This is often a narrow part of a road, perhaps also with a smaller number of lanes, or a reduction of the number of tracks of a railway line.
  • In engineering, a bottleneck is a phenomenon by which the performance or capacity of an entire system is severely limited by a single component.
  • A bottleneck in project management is one process in a chain of processes, such that its limited capacity reduces the capacity of the whole chain.

As we continue our discussion, a key point from these definitions to keep in mind is the “singular” characteristic. Additionally, I’ll infer a “stationary” characteristic as well for the bottleneck throughout the time reflected by the example CFDs that follow. (more…)

Little’s Law: Isn’t It a Linear Relationship?

“Here’s the bottom line: the number one driver for shipping products quicker is by focusing on the important ones and killing the unimportant ones.”

“You might be thinking: ‘True, but couldn’t we also increase the average completion rate’? You’re right, but the impact of doing that is much lower than reducing the TIP (things-in-process) — that is, influencing the average completion rate is rather difficult and is often a function of available resources, scope creep, market demands and changes, etc.”

– Pete Abilla, Nov 2006, Little’s Law for Product Development

A few weeks back Arne Roock (see his posts here), a fellow kanban/lean-agile practitioner, pinged me with a question related to Little’s Law and utilization. Paraphrasing, essentially it was “Queuing theory states that the speed of networks decreases dramatically (non-linearly) as utilization increases more than 80%. But according to Little‘s Law (given a stable system), Lead Time increases linearly if we increase WIP (which increases utilization). Why doesn’t Little’s Law show lead time going up exponentially from a certain point on (ex. past 80% utilization)?” This resulted in exchanging a couple emails discussing the use of Little’s Law, and why and how in the software development context an increase in work-in-progress could result in a non-linear increase in lead time. This post captures and reflects some of the thoughts we shared. My assumption is you’ve wondered too about similar questions. If so, I hope you’ll find this post interesting and helpful. (more…)

Business and Technology Peacefully Co-creating

Written in direct collaboration with Richard Hensley (McKesson AVP).

“Knowledge is an unending adventure at the edge of Uncertainty.” – Jacob Bronowski, British mathematician, biologist, historian of science, poet, inventor, author of “The Ascent of Man”

“Maturity of mind is the capacity to endure Uncertainty.” – John Huston Finley, 1938 – New York Times editor-in-chief

“Many high performers would rather do the wrong thing well than do the right thing poorly.” – Thomas J. Delong & Sara DeLong, “Managing Yourself: The Paradox of Excellence”, June 2011 – Harvard Business Review

It’s common to see an organization (the people in them) focus on building systems with as many features as possible and targeting delivery by a specific due date. Yet, often the result is missing the date while also ignoring other important goals demanded by the businesses such as high levels of product quality, development productivity, planning reliability, employee satisfaction, and customer loyalty. Retrospectives, if done after such an occurrence, surface the dissatisfaction concerning missed dates, poor quality, technical debt, and more, still frequently this pattern repeats. Does this scenario sound familiar to you? If so, why do you think it is so? In a past or maybe your current organization, I’m guessing you’ve heard or thought, “We need our business and technology people on the same page.” How might “being on the same page” look in your organization? Does your current software development methodology, its principles, processes, and practices, contribute effectively to this objective? Is getting on the “same page” with objectives and goals enough?

Over the last three years Richard Hensley, AVP Process at McKesson Health Solutions, has worked to address these challenges within the three business units of the division he works in at McKesson. I’ve been able to catch up with him on several occasions and discuss his efforts over these years. This post is a brief “fly-over” of his experience, capturing some of the key thoughts Richard developed over this time, and shared during our conversations.

No Silver Bullets Here!

Anyone reading a blog post on getting business and technology people on the same page probably knows there is no “silver bullet” to this challenge. Chances are good you’ve already been a part of such an effort, right? If so, you know it is not a simple task. Or even if you saw them start out on the same page in your organization, did issues appear that caused this working relationship to return to its earlier challenging state?

In short, Richard suggests, “you won’t find quick fixes for this issue” and his experience indicates it takes a serious effort from both sides. It also requires a continuous commitment over time because “getting everyone on the same page is a good start but not sufficient to sustain the business.” Yes, getting on the same page upfront, by itself, can be a positive thing as it helps everyone feel good, knowing where others are at and being in the know. If you’re familiar with the practice of daily stand-ups, you can draw a comparison, getting on the same page only is like a stand-up where team members simply provide “status” of their work. It is a good start, but alone it is ineffective for helping to solve real issues. In a similar fashion, getting on the same page with objectives and goals, if that is all you do, doesn’t help anyone address how things might be done more quickly or more effectively. It is a good start, but more is needed! (more…)

Lesson from LSSC 2012: Focus on Learning to Learn!

“The possession of tools, techniques, and technology is not the competitive advantage…it’s the learning you wrap around them before anyone else.”
– Steven J. Spear, Senior Lecturer – MIT Sloan School of Management & Engineering Systems Division – May, LSSC 2012, Boston

“Specifications should come more toward the end of the project not the start…capture knowledge for future use – both successes and failures.”
– Michael Kennedy, author of “Ready, Set, Dominate”, retired Senior Member, Technical Staff after 31 years at Texas Instruments Defense Electronics – May, LSSC 2012, Boston

“I’ll probably annoy a few system thinkers as well as proponents for self-organizing teams, but that means I’m doing my job…extremes of centralization and de-centralization are sub-optimal.”
– Don Reinertsen, educator at California Institute of Technology , author of “Product Development Flow” – May, LSSC 2012, Boston

“Today, I’d like to be provocative, not obnoxious because I think that is the place to be…pushing people to work faster is not as effective as working on the interfaces (the handoffs).”
– Gregory A. Howell, educator, author, and co-founder & managing director of the Lean Construction Institute (LCI) – May, LSSC 2012, Boston

 “Experience is not the same as knowledge (remember from which you are answering a question).”
– Yochai Benkler, Professor of Entrepreneurial Legal Studies at Harvard, and faculty co-director of the Berkman Center for Internet and Society – May, LSSC 2012, Boston

If you missed the Lean Software and Systems Consortium 2012 (LSSC 2012) conference in Boston and you’re looking for an overview of the keys from the keynotes, highlights from the presentations, or a taste of the pre and post conference happenings, I can point you to several posts that do that very well here, here, here, and here. (Note these conferences going forward are now referred to as Lean Kanban North America or LKNA conferences).

Here’s My Take on the Lean Software Systems Consortium 2012 Conference

An alternative perspective of LSSC 2012 that I’ll offer you orbits more narrowly around my single biggest takeaway. It wasn’t a single keynote talk or individual track presentation, it wasn’t some succinct brilliant message appearing in the titles for any of the keynote talks or track presentations, nor was it overtly offered as “the main point” for any of the keynote talks or the track presentations that I saw. It was, for me, an unmistakable message noticeably and repeatedly threaded, as the underlying (core) lesson, into the themes of the keynote talks and several of the presentations I attended. “Focus on Learning to Learn” emerged as my “un-official theme” for the conference and was the key takeaway from LSSC 2012.

On the surface that sounds a bit obvious doesn’t it? Learning is the focus or purpose of most any conference, right? Okay, I do wonder about some that occur year after year in the same resort places, but that’s for another time and place. Yes, of course, “learning” is the focus of most any conference. To be clear though, I’m specifically saying, “learning to learn” here, not just “learning.” What’s the difference? 1 (more…)

A Few Basic Ways to Visualize Story Lead Time Predictability

Note: My colleague 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” which you can learn more about here.

“The ability to take data – to be able to understand it, to process it, to extract value from it, to visualize it, to communicate it, it’s going to be a hugely important skill in the next decades, not only at the professional level but even at the educational level for elementary school kids, for high school kids, for college kids. Now we really do have essentially free and ubiquitous data. So the complimentary scarce factor is the ability to understand that data and extract value from it.”

“I think statisticians are part of it, but it’s just a part. You also want to be able to visualize the data, communicate the data, and utilize it effectively. But I do think those skills – of being able to access, understand, and communicate the insights you get from data analysis – are going to be extremely important. Managers need to be able to access and understand the data themselves.

 – Hal Varian, Google’s Chief Economist, Jan 2009 – The McKinsey Quarterly

My previous post discussed how some of my earlier teams used T-shirt sizes for story level work items in their software development planning processes. But T-shirt sizes were only a part of what helped us get effectively predictable. The emphasis on just-in-time (JIT) story creation and story analysis, along with just-enough story and portfolio level backlogs (limiting work-in-progress or WIP), were also significant contributing factors. Two other key factors were de-emphasizing upfront estimating of level-of-effort and duration, and instead placing a greater emphasis on lightweight tracking of real (lead and cycle) times to complete and deliver story level work items. (See my earlier posts here and here for a bit more context and background on push vs. pull scheduling systems.)

I also discussed how some basic analysis of this lead time data and T-Shirt sizing helped us develop an internal service level of agreement (SLA) for completing story level work items. But this information also guided and shaped the policies we developed to influence the team’s interactions and specific responses (pulled from our toolbox) in a JIT manner as information unfolded about a story’s level of effort and duration. My observation is that all this contributed to us becoming predictable in a context where we never had been before using heavier upfront planning strategies. Based on my study of scheduling systems this combination reflected key pull scheduling characteristics, where the role of our software development workflow management changed from determining all operation activities upfront, to one focused much more on setting the rules for interactions (in turn influencing our work environment structures).

There’s lots more analysis (mathematical and statistical) you can do using the minimal and easily collected data that produced the Basic Story (Lead Time) Metrics table and T-shirt sizes from my earlier post and that will have to wait for another time. For this post I want to focus on visualizing the information in this simple table to see if we might extract a bit more value from the modest analysis investment already expended.

I’ll also build on this initial visualization, using a bit more (quick) low hanging fruit type analysis of the full raw data set represented by the earlier spreadsheet snippet, to produce a basic temporal (time) perspective of story lead times. Can adding a basic temporal perspective  provide a number of other useful insights into understanding the nature of our workflow’s story level work item lead times? (Both the earlier table and spreadsheet snippet are included here; click images to enlarge). To this basic temporal perspective, with a bit more new analysis on the existing raw data spreadsheet, I’ll then add new information extracted to give a work item type perspective as well, and then overlay the T-shirt size information to this mix.

Finally, again with just a bit more analysis on the existing raw data, I’ll visualize two other separate temporal perspectives using both  percentages and frequency counts. Afterwards, let me know what you think. Do one or two of these other ways of visualizing the information in the earlier table and spreadsheet snippets help you and others access, understand, and communicate insights that leads to a more effective predictable workflow in your software development context? (more…)