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Empirical or Definitive

Ever heard of the cone of uncertainty?  The cone shows the historical error at certain time periods in a tropical cyclone forecast.  What happens today and what has happened in the past is pretty much all we know.  We can certainly use all kinds of scientifically proven processes or models to try to predict the future.  But, in the end, we won’t know what tomorrow will bring until tomorrow.  If you are dealing with machines, you should be able to predict upcoming events with relative certainty.  If you are dealing with people or something like mother nature, the odds of predicting events with certainty are slim to none.

We need to assume that baselines may change significantly during a project or in life.  In unpredictable environments, empirical methods should be used to monitor progress and direct change, rather than using definitive methods to try and predict progress and stop change.


You work and work and work, trying to lock in your scope, your schedule, and your budget before the project even begins.  You do everything you can to lay it all out, attempting to account for every possible variable.  Unfortunately, you don’t know what tomorrow will bring.  So, the further out the schedule goes, the greater the risk something is going to change.  What’s it going to be?  Is scope going to change or maybe the schedule will slip?  With the cone of uncertainty, whatever foreseen changes are ahead, there are going to be exponentially more unforeseen the further out the schedule goes.


In reality, you begin with the greatest unknown.  Even some of the unknowns aren’t even known.  Just accept it!  You’re not the Amazing Kreskin.  You can’t predict the future.  The only thing that is guaranteed is something is going to change.  So, plan for that change.  Know the goal you’re trying to reach.  Keep your eye on that goal.  Now, do what you do.  Develop, lead, manage… it doesn’t matter.  What does matter is you see where you are right now, know where you want to go, and then at a measured time, see where you are again.  Make some adjustments and repeat.  You will find if you just accept the change, you can use it to your advantage to get closer and closer to your goal.


You can not predict the future, only plan for it.  You can not steer a hurricane, only plan for it.  You can not prevent change…  Can you guess what comes next?  That’s right, you plan for it.

About Derek Huether

I'm an Enterprise Agile Coach at LeadingAgile. I have a goal to take the hand waving out of Agile, Kanban, & Scrum. I’m a strange combination of a little OCD, a little ADHD, a lot of grit, and a lot of drive. I come from a traditional PM background but I don't give points for stuff done behind the scenes. The only thing that counts is what you get done and delivered. Author of Zombie Project Management (available on Amazon)

3 Responses to “Empirical or Definitive”

  1. July 2, 2011 at 5:23 pm

    Once again the statement “you cannot predict the future,” is erroneous. You certainly can predict the future IF you have error bands for the predictions in the future. The “cone of uncertainty” is exactly a prediction of the future, You’re diagram shows it. There is a moderate probability that the Atlantic storms will stay within the east and west bounds of the tracks that have occurred over then past 1000 years.

    Please consider not using “we cannot predict the future” again, but instead start using predictions with variances (error bands). Point estimates in the absence of variance and the underlying probability distributions that generated those variances are of little use in the real world. Now’s the chance to start correcting that erroneous understanding for all those who believe point estimates are acceptable

    • Anonymous
      July 4, 2011 at 12:04 am

      Glen, I certainly see your point. There is a moderate probability. But probability does not equal certainty, unless you said there was a 100% probability. But, I still don’t believe in absolute certainties. I believe anything is possible, though highly improbable. Unfortunately, the blog title “We cannot predict the future…unless we start predictions with variances (error bands)” doesn’t quite roll off the tongue.

      I do appreciate the comment.

  2. Anonymous
    July 24, 2011 at 12:23 pm

    Actually, according to DID 81650, it shall be applied to contracts that require Earned Value Management (EVM) and other contracts based on the contract risk assessment. Being I don’t work in the federal acquisition space, I am not constrained by the DID and neither are many who read this blog. When those within the 81650 culture stop quoting it like it is gospel, perhaps more will be willing to listen. Until then, we’ll be stuck in a world of having humor those who think they know best.

    Since my clients have been happy with my performance, quantified by continuous feedback requests, I’ll worry out the blog titles and let you continue to win the hearts and minds in the federal acquisition space.

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