I was browsing through the ample pages of the National BIM Standard produced by NIBS and came across a thing called the Capability Maturity Model. It's a spread sheet for determining how much you are, ah... BIMing and what is minimum BIM. You can download the Minimum BIM spreadsheet here.
It is complex, but all the information you need to start is in the spread sheet itself. I wish I scored a tad bit higher, but we all have to start somewhere I guess. I found a much longer article with Way More information. It's worth reading if you found this at all interesting.