#NoEstimates: knowing the difference between an estimate, a forecast and a promise

A few weeks ago I attended a NoEstimates workshop held by Woody Zuill and Vasco Duarte in Helsinki. It has been an intense and fruitful day and here is the main insight I brought back home.

The day was led with a very nice pace, the two speakers showing a very different style in explaining their ideas. Their continuous turnover on stage made the workshop very light to follow though packed-up with contents.

The concepts explained during the workshop resonated a lot with what I have discovered through the years about planning product or software development: an estimate is not a promise and both are not a forecast. The first two are quite unhandy too.

According to Merriam-Webster, an estimate is

an opinion on the nature, character, or quality of something.

forecasting is

to calculate or predict (some future event or condition) usually as a result of study and analysis of available pertinent data predict

while a promise is

a statement telling someone that you will definitely do something or that something will definitely happen in the future

Well, that’s enough to spot a linguistic abuse: we are always asked for an estimate, thus for an opinion, while we are committing to a promise and no one cares enough about forecasting – if any useful at all.

I would recommend this workshop to anyone willing to get out of the big bubble lie “sharp estimation is the key factor for success”.

One thought on “#NoEstimates: knowing the difference between an estimate, a forecast and a promise

  1. Henrik

    I think you’ve got it a bit wrong here, and are mixing nouns and verbs 🙂

    Customers aren’t really interested in being handed an estimate (the noun), they want us to *estimate* (the verb). I.e they’re are more interested in the outcome of the activity. Same thing with promises – they don’t want to be handed a promise (noun) the want us to promise (verb).

    So, comparing verbs:

    Estimate (http://www.merriam-webster.com/dictionary/estimate)
    “to give or form a general idea about the value, size, or cost of (something) : to make an estimate of (something)”

    Forecast (http://www.merriam-webster.com/dictionary/forecast)
    “to say that (something) will happen in the future : to predict (something, such as weather) after looking at the information that is available”

    Promise (http://www.merriam-webster.com/dictionary/promise)
    “to tell someone that you will definitely do something or that something will definitely happen in the future”
    “to make (something) seem likely : to show signs of (something that is likely or expected to happen)”

    And by these definitions, I can clearly see how “to forecast” actually is a more specific activity of “to estimate”. When we say that something will happen in the future or predict something (about building software), then we have to include an idea about the value, size or cost.

    Thanks!

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