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1 January 2012

Planning for optimal ‘flow’ in an uncertain world

Filed under: Agile, books, critical chain, flow, lean, predictability — David Wood @ 1:44 pm

In a world with enormous uncertainty, what is the best planning methodology?

I’ve long been sceptical about elaborate planning – hence my enthusiasm for what’s often called ‘agile‘ and ‘lean‘ development processes.  Indeed, I devoted a significant chunk of my book “Symbian for software leaders – principles of successful smartphone development projects” to comparing and contrasting the “plan is king” approach to an agile approach.

But the passage of time accumulates deeper insight.  Key thinkers in this field now refer to “second generation lean product development”.  Perhaps paramount among these thinkers is the veteran analyst of best practice in new product development, Donald Reinertsen.  I’ve been influenced by his ideas more than once in my career already:

  • In the early 1990s, while I was a software engineering manager at Psion, my boss at the time recommended I read Reinertsen’s “Developing Products in Half the Time“. It was great advice!
  • In the early 200xs, while I was EVP at Symbian, I remember enjoying insights from Reinsertsen’s “Managing the Design Factory“.

I was recently pleased to discover Reinertsen has put pen to paper again.  The result is “The Principles of Product Development Flow: Second Generation Lean Product Development“.

The following Amazon.com review of the latest book, by Maurice Hagar, persuaded me to purchase that book:

This new standard on lean product and software development challenges orthodox thinking on every side and is required reading. It’s fairly technical and not an easy read but well worth the effort.

For the traditionalist, add to cart if you want to learn:

  • Why prioritizing work “on the basis of project profitability measures like return on investment (ROI)” is a mistake
  • Why we should manage queues instead of timelines
  • Why “trying to estimate the amount of work in queue” is a waste of time
  • Why our focus on efficiency, capacity utilization, and preventing and correcting deviations from the plan “are fundamentally wrong”
  • Why “systematic top-down design of the entire system” is risky
  • Why bottom-up estimating is flawed
  • Why reducing defects may be costing us money
  • Why we should “watch the work product, not the worker”
  • Why rewarding specialization is a bad idea
  • Why centralizing control in project management offices and information systems is dangerous
  • Why a bad decision made rapidly “is far better” than the right decision made late and “one of the biggest mistakes a leader could make is to stifle initiative”
  •  Why communicating failures is more important than communicating successes

For the Agilist, add to cart if you want to learn:

  • Why command-and-control is essential to prevent misalignment, local optimization, chaos, even disaster
  • Why traditional conformance to a plan and strong change control and risk management is sometimes preferable to adaptive management
  • Why the economies of scale from centralized, shared resources are sometimes preferable to dedicated teams
  • Why clear roles and boundaries are sometimes preferable to swarming “the way five-year-olds approach soccer”
  • Why predictable behavior is more important than shared values for building trust and teamwork
  • Why even professionals should have synchronized coffee breaks…

Even in the first few pages, I’ve found some cracking good quotes.

Here’s one on economics and “the cost of late changes”:

Our central premise is that we do product development to make money.  This economic goal permits us to use economic thinking and allows us to see many issues with a fresh point of view.  It illuminates the grave problems with the current orthodoxy.

The current orthodoxy does not focus on understanding deeper economic relationships.  Instead, it is, at best, based on observing correlations between pairs of proxy variables.  For example, it observes that late design changes have higher costs than early design changes, and prescribes front-loading problem solving.  This ignores the fact that late changes can also create enormous economic value.  The economic effect of a late change can only be evaluated by considering its complete economic impact.

And on “worship of conformance”:

In addition to deeply misunderstanding variability, today’s product developers have deep-rooted misconceptions on how to react to this variability.  They believe that they should always strive to make actual performance conform to the original plan.  They assume that the benefit of correcting a deviation from the plan will always exceed the cost of doing so.  This places completely unwarranted trust in the original plan, and it blocks companies from exploiting emergent opportunities.  Such behaviour makes no economic sense.

We live in an uncertain world.  We must recognise that our original plan was based on noisy data, viewed from a long time-horizon…  Emergent information completely changes the economics of our original choice.  In such cases, blindly insisting on conformance to the original plan destroys economic value.

To manage product development effectively, we must recognise that valuable new information is constantly arriving throughout the development cycle.  Rather than remaining frozen in time, locked to the original plan, we must learn to make good economic choices using this emerging information.

Conformance to the original plan has become another obstacle blocking our ability to make good economic choices.  Once again, we have a case of a proxy variable, conformance, obscuring the real issue, which is making good economic decisions…

Next, on flow control and the sequencing of tasks:

We are interested in finding economically optimum sequences for tasks.  Current practices use fairly crude approaches to sequencing.

For example, it suggests that if subsystem B depends on subsystem A, it would be better to sequence the design of A first.  This logic optimises efficiency as a proxy variable.  When we consider overall economics, as we do in this book, we often reach different conclusions.  For example, it may be better to develop both A and B simultaneously, despite the risk of inefficient rework, because parallel development can save cycle time.

In this book, our model for flow control will not be manufacturing systems, since these systems primarily deal with predictable and homogeneous flows.  Instead, we will look at lessons that can be learned from telecommunications networks and computer operating systems.  Both of these domains have decades of experience dealing with non-homogeneous and highly variable flows.

Finally, on fast feedback:

Developers rely on feedback to influence subsequent choices.  Or, at least, they should.  Unfortunately, our current orthodoxy views feedback as an element of an undesirable rework loop.  It asserts that we should prevent the need for rework by having engineers design things right the first time.

We will present a radically different view, suggesting that feedback is what permits us to operate our product development process effectively in a very noisy environment.  Feedback allows us to efficiently adapt to unpredictability.

To be clear, Reinertsen’s book doesn’t just point out issues with what he calls “current practice” or “orthodoxy”.  He also points out shortcomings in various first generation lean models, such as Eliyahu Goldratt’s “Critical Chain” methodology (as described in Goldratt’s “Theory of Constraints”), and Kanban.  For example, in discussing the minimisation of Work In Process (WIP) inventory, Reinertsen says the following:

WIP constraints are a powerful way to gain control over cycle time in the presence of variability.  This is particularly important where variability accumulates, such as in product development…

We will discuss two common methods of constraining WIP: the kanban system and Goldratt’s Theory of Constraints.  These methods are relatively static.  We will also examine how telecommunications networks use WIP constraints in a much more dynamic way.  Once again, telecommunications networks are interesting to us as product developers, because they deal successfully with inherently high variability.

Hopefully that’s a good set of tasters for what will follow!

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