I'm always intrigued when I run into a situation where I don't have an immediate solution.  It forces more in-depth thought which can help us revise our view of how the world works.

This week brought just an opportunity ... how to apply root cause analysis to a situation where the outcome of a process is to quantify an unknown (e.g., there are no specs), and when the process took place a long time ago.  I have a long drive coming up soon and it will provide lots of time for thinking this through.

In the meantime it helped focus me back on the importance of process control, and the need to knowing the relative contribution of each factor.  Far too many organizations just treat all of them as if they were equal.