I think every analyst out there should have a poster like this hanging right in front of their face (o.k. I just pinned mine 2 min's ago!). Unless every thought on that grid is not worked out, no amount of information on what happens to a business is ever worth it.
Simple equation= Fantastic results
Just in case my image is unreadable,
Internal Origin/ are attributes of the organization
External Origin/ are attributes of the enviorment
Helpful/Harmful to achieving the Objective