"Unk-unks" 4 Oct 2007

You probably remember the infamous "known unknown" speech that Donald Rumsfeld made in 2002:

"Reports that say that something hasn't happened are always interesting to me, because as we know, there are 'known knowns'; there are things we know we know. We also know there are 'known unknowns'; that is to say we know there are some things we do not know. But there are also 'unknown unknowns' - the ones we don't know we don't know.'"

...Well, it turns out that, despite the ridicule he received, Rumsfeld was actually quoting an accepted project management theory: The theory of managing "unk-unks" (a contraction of "unknown unknowns" - i.e. problems that have not been and could not have been imagined or anticipated).

Tom Scott points out that there are two main methods of dealing with unk-unks:

"Either, you hedge against [them] by developing on parallel lines and hope that one works out. This is the approach many designers take - they prototype lots of ideas knowing that only one will be picked, and no one can predict which one before all have been seen. Alternatively you can manage the unk unks as they emerge, by changing the approach in response to new information.

"If you want to take this second approach then the team needs to be empowered to solve problems en route (rather than only being allowed to build to an existing design and plan). However, in my experience the senior management and/or product owner must also be intimately involved in the project, have sufficient knowledge to check the plausibility of changes, and be supportive of the mid-course corrections."

At Etre, we adopt a third approach. Rather than prototyping lots of different ideas and then picking the best one (per Scott's first method), we start with a single paper prototype and then iteratively design-test-redesign it - making enhancements at each stage. If the prototype tests well during a cycle, we increase its fidelity - for example, we might upgrade a paper prototype to a barebones HTML prototype. If not we revise the existing prototype and retest. Until eventually we arrive at our "production ready" solution. This phased approach works well for us, as the biggest unk-unks are usually identified and dealt with while we're still working on paper, which means that we can make changes to our design quickly, easily and without great expense. We'd be interested to know how you manage unk-unks however...