Lean: Development is not Manufacturing

The conclusions of lean manufacturing theories are not necessarily valid in the domain of (software) product development.

There’s good reasons why it’s so difficult to fix time, budget, and feature scope all at once in a software development project.

I’ve been listening to a talk by Don Reinertsen, and one of his points, although not the main point, is about variability:  if you could reduce variability in the workflow by 10%, or you could reduce capacity utilization by 10%, by far you would prefer to reduce capacity utilization.  That’s where the economic payoff is.

The reason is that increased capacity utilization increases queue size and lead time exponentially.  In other words, if you try to keep all your resources busy all the time, everything takes forever to finish.  This goes for both manufacturing and development.  Variability in workflow, however, is bad in manufacturing, but can’t be avoided in product development, and might even be exploited.

So what else is different about development compared to manufacturing?

Manufacturing Development
Tasks are…. repetitive non-repetitive
Tasks are… predictable unpredictable
Requirements are… a constraint a degree of freedom
Requirements are… fixed evolving
Cost of delay is… homogeneous non-homogeneous
Task durations are… homogeneous non-homogeneous
Variability is… always waste not always waste
Inventory is… physical objects information
Inventory is… visible invisible

A talk by Don Reinertsen,
Second Generation Lean Product Development: From Cargo Cult to Science

agile adoption fails in a “fixed project situation”

i saw an interesting article on infoq.com.

the term “fixed bid” is used in the article, but this article applies to another “fixed project situation“, too, i.e., where the resources are fixed, and there’s a specified, promised feature scope and a specified, promised delivery date. 

(btw, it isn’t really possible to control all of resources, delivery date, and scope and quality of features at the same time…)

In an agile software team you don’t estimate your work till right
before you begin. And you only estimate, in the case of Scrum, the next
iterations work. So how do you know how long it will take? You don’t.
Furthermore, you really don’t care.
You’ll continue to deliver
functionality every iteration. As soon as product management and QA say
you have a good enough product; it’ll be released as a production
version. You might have a guess, but until the team estimates it….you
really don’t know long it will take.

In a fixed bid situation….your estimation needs to take place up front.
In the 2nd scenario, if I told the team, … “we’re using Scrum”: they’d estimate the work
the next iteration. They would assume their estimates would be taken
seriously and you’d give them time to complete the work as it unfolds
regardless of whether their estimates fit your original project funding
or not. That’s only fair.

alternatively: they would assume they’d get the “time to complete the work with high quality regardless of whether their updated estimates fit your original project plan and delivery date or not”.

[this leads to failure]….at managing the project and therefore…….”this agile thing doesn’t work”.

The mistake was to assume the company’s leadership … was
organizationally committed to … agile principles. The mere fact
that they are asking you to estimate the funding you’ll need to
complete the project tells us otherwise.

alternatively: the fact that they are asking you to commit to a fixed feature set and a fixed delivery date tells us otherwise. 

this isn’t bad, per se, it just isn’t agile.

[the real problem]

  • Agile is often assumed … to be a development process with no impact on budgeting. This is not the case.
  • Development teams assume leadership understands the implications of adopting agile at the budgetary level.

Developers and development teams often have zero visibility into
budgeting so they are unaware of how their agile efforts are being
accounted for in monetary terms. …. Likewise, management is often ignorant of
development and specifically agile development practices. Agile
adoption requires education to ease the clash and misunderstanding of
these two worlds.

So what are some of the consequences of attempting to adopt agile
practices on a fixed bid project
…essentially laying an agile façade
over the waterfall project

Agile does away with the need for a project manager. …. organizing and managing the development effort are more centered on
technical leadership, task and risk management. Timelines and budgets
go out the door.
if you’re in a non-agile situation … then traditional PM practices are … essential

Doing iteration planning in a fixed bid situation will almost certainly
result in confusion, budget variances, and/or loss of functionality.


In fixed bid scenarios the question is not … how much
functionality the team is doing per time period
. It really doesn’t
matter. They need to get all the functionality done

So using … iterations in a fixed bid project sends the wrong signal to the team and your customers.

using iterations in a fixed project situation sends the wrong signal to the team.

you can still visualize workflow, f.ex. with kanban, reduce work in process, do stand up meetings (very short, impediments only), etc.

but in general you should try to get out of a fixed project situation before trying to go agile.

Edit: About that last part… I think there’s a few basic, agile tools you can utilize whatever you’re doing: visualize how you work; get faster feedback; limit the amount of work in progress.

software projects: have your cake and eat it?

would you like to have your cake and eat it, too?

in my opinion you actually can’t; you’re not able to make absolutely sure that a project is on budget (resources), on time (delivery date), and have all the planned features with high quality, all at the same time.  there’s always a risk, and you can only control any 2 out of the 3 factors at the most. If you try to control all 3 factors at once you are most likely sacrificing the quality of the features, and thus you’re not in control over the features anyway.

Scott W. Ambler makes a few interesting points in this article about software development projects – i’ve selected the quotes that’s most interesting (to me) below.

  • “the only true measure of progress on a software development project is the delivery of working software. “
  • “Agile teams choose to produce potentially-shippable software at the end of each iteration, providing concrete and visible feedback to their stakeholders as to their actual progress. “
  • “… the majority of stakeholders prefer this sort of tangible evidence of progress instead of intangible numbers. “
  • “… the majority of our stakeholders aren’t really interested in whether we’re on schedule or on budget.”

“…. In August 2007, Dr. Dobb’s ran a survey exploring how people define IT project success, and we found that 80 percent of people preferred to focus on producing a good return on investment (ROI) than being under budget, and that 62 percent wanted teams to ship their systems when they’re ready to be shipped rather than forcing adherence to a schedule. ”

  • “… the priorities are to spend the money wisely and ship quality systems. “
  • “… shipping high quality software is more important than being on time and on budget”
  • “… instead of measuring progress against your plan, … you should instead be focusing on ensuring ROI and product quality. “

“The agile practices of implementing requirements in priority order and allowing requirements to evolve throughout the lifecycle ensure greater ROI, and agile practices such as test-driven development (TDD) and refactoring promote greater quality.”