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Jurgen Appelo calls himself a creative networker. But sometimes he's a writer, speaker, trainer, entrepreneur, illustrator, manager, blogger, reader, dreamer, leader, freethinker, or… Dutch guy. Since 2008 Jurgen writes a popular blog at, covering the creative economy, agile management, and personal development. He is the author of the book Management 3.0, which describes the role of the manager in agile organizations. And he wrote the little book How to Change the World, which describes a supermodel for change management. Jurgen is CEO of the business network Happy Melly, and co-founder of the Agile Lean Europe network and the Stoos Network. He is also a speaker who is regularly invited to talk at business seminars and conferences around the world. After studying Software Engineering at the Delft University of Technology, and earning his Master’s degree in 1994, Jurgen Appelo has busied himself starting up and leading a variety of Dutch businesses, always in the position of team leader, manager, or executive. Jurgen has experience in leading a horde of 100 software developers, development managers, project managers, business consultants, service managers, and kangaroos, some of which he hired accidentally. Nowadays he works full-time managing the Happy Melly ecosystem, developing innovative courseware, books, and other types of original content. But sometimes Jurgen puts it all aside to spend time on his ever-growing collection of science fiction and fantasy literature, which he stacks in a self-designed book case. It is 4 meters high. Jurgen lives in Rotterdam (The Netherlands) -- and in Brussels (Belgium) -- with his partner Raoul. He has two kids, and an imaginary hamster called George. Jurgen has posted 145 posts at DZone. You can read more from them at their website. View Full User Profile

How to Deal with Unknown Unknowns

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Getting people together to share information and make joint decisions is the best way to deal with the unknown.

Software projects always suffer from limited predictability. And that’s not only because of the many feedback loops inside the system. Another reason is that every team has to face the unknown.

The Incompressibility Principle
”There is no accurate (or rather, perfect) representation of the system which is simpler than the system itself. In building representations of open systems, we are forced to leave things out, and since the effects of these omissions are nonlinear, we cannot predict their magnitude.” - Cilliers, Paul. "Knowing Complex Systems" Richardson K.A. Managing Organizational Complexity: Philosophy, Theory and Application.

From the Incompressibility Principle we can infer there will always be unknowns. There are things unknown about the system itself, and things unknown about the environment.

Known Unknowns

Joker We can distinguish two kinds of unknowns. The known unknowns are the things we know that we don’t know. For example, we know that the customer will sometimes change her mind. But we don’t know when and in which cases. And we know there’s a chance that team members will get sick. We just don’t know who and when. I sometimes refer to these kinds of risks as jokers. We know the jokers are in the deck of cards. We just don’t know which hands will get them.

Unknown Unknowns

Black-swan The unknown unknowns are the things we don’t know that we don’t know. For example, I was once confronted with a team member who had, quite unexpectedly, developed a psychological disorder. And I once unexpectedly became chairman of an institution, when the other two board members quit one month after I joined the board. I had never dealt with such situations before, and I had not taken these eventualities into account in my decisions. Such events are sometimes called black swans.

Not long ago people could imagine only white swans, because white swans were all they had ever seen. And so people predicted that every next swan they would see would be white. The discovery of black swans shattered this prediction. The black swan is a metaphor for the uselessness of predictions that are based on earlier experiences, in the presence of unknown unknowns. - Also see: Taleb, Nassim. The Black Swan.

Limited Knowledge

It is important to understand that the unknown always depends on the observer. Some people already knew about black swans, but that didn’t make them any less surprising to those who had never seen them. My fellow board members already knew they wanted to leave their positions a good time before they shocked me with their announcements. And if one of your team members turns out to be a criminal on the FBI’s Top 10 Most Wanted list, he probably knew that long before you found out.


The known unknowns and unknown unknowns in your organization differ from person to person. Getting people together to share information and make joint decisions is the best way to deal with the unknown.

This text is an excerpt from the Agile Management course, available from March 2011 in various countries.

Published at DZone with permission of its author, Jurgen Appelo. (source)

(Note: Opinions expressed in this article and its replies are the opinions of their respective authors and not those of DZone, Inc.)



Emma Watson replied on Fri, 2012/03/30 - 3:02am

Just a comment, when you use the term "system" you implicitly assume an organizational system. This is not clear for those of us working "product" systems - machines, production facilities. In this "machines" world, much of the variability and uncertainty around "people" is boxed by the staff selection process. Performance of individuals is "ruthlessly" controlled through the selection and management process on high risk programs in our domain.

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