When Should Waterfall be Used Instead of Agile?

I just read a thread on the Scrum Development yahoo user group about when it would be appropriate to use agile and when waterfall would be better.

This brought to mind all the conversations I’ve had over the years regarding “when to use agile”. There are many folks in organizations that believe that waterfall is best suited for some projects.

So, I’ve been searching for those “types” of projects.

Now, let’s be clear. I am using the term “waterfall” in the strictest sense which means that:

  • Requirements have to be complete and signed off before technical design begins.
  • Technical design has to be complete before development begins.
  • All coding has to be complete for testing begins.

If we “kind of” follow this, then it is chaos.  The question we have to ask is … is it even possible to meet the strict requirements of waterfall?  My answer is NO for software projects, or any projects with a large amount of unknowns or required creativity and flexibility.

Can you ever successfully elicit and document a complete set of requirements at the most granular level?  This is what waterfall requires after all. If there is even a remote chance that a) the customer isn’t sure what they want, b) the customer may change their mind on what they want, or c) there is even a small amount of complexity, then it is very, very high risk and just not very smart to use waterfall. You just can’t…stop kidding yourself.

So, is there ever a reason why you would want to use waterfall? Sure! Here they are:

  • The culture is not ready to work cross-functionally.
    • Any agile methodology requires a cross-functional team. If the culture cannot sustain cross-functional work then you are forced into communication by documentation. Yeah, good luck with that. You should think about coming up with a strategy to make people hunger for cross-functional collaboration.
    • Not everyone “wants” to work in a cross-functional team environment. They need to either be coached up or coached out.
  • Management makes you use waterfall.
  • You can confidently define everything up front, there is little or no chance there will be changes, and there are no unknowns.

Let’s not pretend anymore that waterfall is actually appropriate for any complex software project with humans working on it.  With complexity come unknowns, and with unknowns, the amount of bureaucracy necessary to handle “change management” is ludicrous.  I have yet to experience any software development project that did not have at least some kind of complexity.  If you say “agile doesn’t work for all software projects”, then you have a misunderstanding of what agile truly is.

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About Andre Simones
I am a founding partner of One80 Services that specializes in agile training, small business and startup guidance, and custom development. My goal is plain and simple. To see others succeed. I want to teach you how stop doing the things that aren't working and give you tools that will empower you to succeed on your own.

One Response to When Should Waterfall be Used Instead of Agile?

  1. David Figueiredo says:

    Hi Andre,

    As a developer/lead/manager with over 25 years of experience, I think I have finally found a use for waterfall. When it fits within a sprint. Ha!

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