Here is a model for organisation analysis in use by (in particular) IT consultancies:
The model assumes, a priori, that these three foci are important; are they?
The only a prior assumption that should be made is that we should look at the organisation as a system. People, processes and IT are all in the system but do not constitute the whole. This model may elevate people, processes or IT to a position where they are viewed as more important/critical than in fact they are. It may lead to solutions which do not, in fact, improve the system.
But it will help sell IT.