Obs vs. Inpt

I work per diem and am fairly new. I know there have been some changes for obs vs inpt procedures recently and was wondering if anyone had a listing of "standard" procedures which are generally considered obs. For example, hysterectomies, lap chole's, hernia repairs? Obs or inpt? I realize those procedures may start out as obs, but considering how things go for the pt post op, they may be changed to inpt status. Thanks.