The HeadScratcher Post Archive
June 2006
How long will it take?

The Headscratcher Post    


June  2006               The Headscratcher Post ©  Headscratchers LLC           Edition 14


How long will it take?  Why is the answer to this question sometimes so inaccurate, and how do you improve on it … A HeadScratcher for sure.


So Mr. Edison … how long will it take you to invent a light bulb that will last long enough to be useful?  Answer … “….”.  Reality … several years.

So Mr. Fixit husband … how long will it take you to put up those bookshelves?

Answer … “About 2 hours”.  Reality … 7 hours (including 3 trips to the hardware store).

So Professional Contractor … how long will it take you to put up those bookshelves?

Answer … “45 minutes”.  Reality … 32 minutes, and the shelves are straight!

So Computer Programmer … how long will it take you to fix that bug? 

Answer … “A few days, possibly a week or two”.  Reality 2.5 hours!

So Another Computer Programmer … how long will it take you to fix that bug? 

Answer … “A day or so”.  Reality 4 days!

So NASA spaceship designer … It is 1960.  How long will it take to put a man on the moon and return him safely.  

Answer … “We could do this by the end of the decade”  Reality … Summer 1969.


What’s the difference?  As you can guess, some it is related to how many times you’ve solved the problem or a similar problem before … called Experience.   It’s also related to probabilities of outcomes.   Lastly is related to how much determination is behind it.


Dissecting what you know.  Chop your knowledge into a couple of pieces:

a)       The things you know how to do because you have done them before.

b)       The things you know you don’t know how to do, but you can compare with things you have done, so you have a good idea of how you might do it.

c)       The things you know you don’t know how to do, and can’t think of anything you can compare it with.

d)       The things you don’t know you don’t know how to do.  Obviously can’t make a list here.  You’re in completely uncharted waters and you don’t know what you are going to discover.


The key is to understand what percentage of the entire effort falls into each category, and what the probability that your guess for the tasks in each category is correct.  


The result is a ”time range” with a confidence level.   Keep cycling until the confidence level is high and the range as narrow as possible.  That becomes the “most probable time range”, and while it won’t give you the right answer every time, you’ll have an improved track record that gets better with practice.


What about Determination?  This is all about compensating for (c) and (d) above, so that you can deliver to your estimate.  This is the other half of “How long is it going to take?”, which is making it happen in the time you said it would, even when surprises occur.  


When you leave for work in the morning you’ve already evaluated what the traffic might be based on a number of factors, like the weather, and estimated how long it will take to drive to work.  However on the way, there’s an accident, and traffic is worse than you estimated.  You compensate … might take a detour, might drive a little faster after you pass the accident, and might skip the morning stop to Starbucks.  By starting with a “reasonable estimate” and compensating for the unknowns, most of the time you’ll be able to overcome the unforeseen obstacle. 


Another way to think about this; You don’t know what barriers might be in your way, but based on track record, focus and commitment, you have high confidence that you, and your team if applicable,  are capable of figuring it out and making things happen in the time that you committed to making them happen.   This is how we got to the moon.  


The Takeaway: The “how long will it take?” question is a recurring HeadScratcher.  It takes the combination of two strategies to have a consistent record of giving an estimate and meeting it.  The first is a better understanding of what goes into the estimate based on what you know and what you don’t and doing some analysis and math .. This gives you a “reasonable estimate”.  The second strategy consists of determination and making things happen in the time allotted by the estimate.  The combination of these enables you to confidently answer the question, “How long will it take?”


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