I was listening to the TED Radio Hour today and ran across a great word: etiology.

It’s the study of causation, as in:

What causes someone to contract polio?

For those of us doing product work, it’s critical to know what causes someone to use a particular feature. What caused this user to run a certain report? What’s causing these other users to create a given workaround?

Your product will improve when you understand the etiology of each user behavior.