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Tuesday, July 08, 2014

What is an Estimate?

If you don’t know what an estimate is, you can’t avoid using them. So here’s my attempt to define what is an estimate.
The "estimates" that I'm concerned about are those that can easily (by omission, incompetence or malice) be turned into commitments. I believe Software Development is better seen as a discovery process (even simple software projects). In this context, commitments remove options and force the teams/companies to follow a plan instead of responding to change.

Here's my definition: "Estimates, in the context of #NoEstimates, are all estimates that can be (on purpose, or by accident) turned into a commitment regarding project work that is not being worked on at the moment when the estimate is made."

The principles behind this definition of an estimate

In this definition I have the following principles in mind:
  • Delay commitment, create options: When we commit to a particular solution up front we forego possible other solutions and, as a consequence we will make the plan harder to change. Each solution comes with explicit and implicit assumptions about what we will tackle in the future, therefore I prefer to commit only to what is needed in order to validate or deliver value to the customer now. This way, I keep my options open regarding the future.
  • Responding to change over following a plan: Following a plan is easy and comforting, especially when plans are detailed and very clear: good plans. That’s why we create plans in the first place! But being easy does not make it right. Sooner or later we are surprised by events we could not predict and are no longer compatible with the plan we created upfront. Estimation up front makes it harder for us to change the plan because as we define the plan in detail, we commit ourselves to following it, mentally and emotionally.
  • Collaboration over contract negotiation: Perhaps one of the most important Agile principles. Even when you spend time and invest time in creating a “perfect” contract there will be situations you cannot foresee. What do you do then? Hopefully by then you’ve established a relationship of trust with the other party. In that case, a simple conversation to review options and chose the best path will be enough. Estimation locks us down and tends to put people on the defensive when things don’t happen as planned. Leaving the estimation open and relying on incremental development with constant focus on validating the value delivered will help both parties come to an agreement when things don’t go as planned. Thereby focusing on collaboration instead of justifying why an estimated release date was missed.
  Here are some examples that fit the definition of Estimates that I outlined above:
  • An estimate of time/duration for work that is several days, weeks or months in the future.
  • An estimate of value that is not part of an experiment (the longer the time-frame the more of a problem it is).
  • A long term estimate of time and/or value that we can only validate after that long term is over.

How do you define Estimates in your work? Are you still doing estimates that fit the definition above? What is making it hard to stop doing such estimates? Share below in the comments what you think of this definition and how you would improve it.

This definition of an estimate was sent to the #NoEstimates mailing list a few weeks ago. If you want to receive exclusive content about #NoEstimates just sign up below. You will receive a regular email on the topic of #NoEstimates as Agile Software Development.

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1 Comments:

  • Hi Vasco,

    What kinds of estimates do not fit your definition?

    (And is it helpful to use the term #noestimates if you actually use certain kinds of estimates?)

    Thanks,

    David.

    By Blogger David Allsopp, at July 15, 2014 12:43 AM  

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