[Ataraxy]

The best way imho to do this is to ignore the individual variables and think about what your business goals and objectives are.

When you have a firm grasp of what those are you can then shape the metrics you are looking at to give you insight into how they effect your overarching goal.

Here's a fantastic piece by the ever amazing Avinash Kaushik that highlights this:

http://www.kaushik.net/avinash/2010/11/web-analytics-maturit...