This Guest article was submitted for publication April 7, 2021.
It is copyright to Payson Hall.
Published here January 2022.

Introduction | Simple Enough? | Estimating
The Big Picture | Take a Closer Look | Conclusion


Is your approach realistic?

In freshman Physics, students learn not to report more precision in their answers than can be justified by the facts of the problem. Why are project managers still expected to report bogus completion dates that imply estimating precision that we don't really have?

How long does it take you to go from your front door to the gate at your local airport? To be clear, I'm talking about baggage is checked and you are through security and ready to stand in line to board. Write down an answer in minutes before you continue. Go ahead, I'll wait.

To answer that question, you probably made assumptions, either implicitly or explicitly. Is the cab waiting outside? Will weather or traffic patterns slow the commute to the airport? Is it a major holiday with heavy air travel expected?

What was your approach?

Did you recall the best time you ever made and write that down? That's optimistic. Did you estimate the average amount of time required? How often to you beat the average? If you only allocated that amount of time, how often would you miss your flight? Did you adjust your estimate to allow for risk? How often do you think you would miss your flight if you used your risk adjusted estimate?

Reflect on your answers and you will learn something about your estimation process. If you were brave and actually wrote down an estimate, would you want to change it or qualify it now that you think more about it? This thought experiment is to get you thinking about the variability in estimates.

If you are a road warrior like me, you have traveled to the airport hundreds of times. You have a sense of how long it takes, but you also know the grief of missing a flight and screwing up your itinerary. I typically plan to be at security an hour before boarding time and enjoy coffee and a leisurely stroll to the gate where I expect to wait for half an hour or so for my flight.

Look at that lonely little number you wrote down — a lot of information about that estimate is hidden.

Simple Enough?  Simple Enough?

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