TOPIC: PMBOK 6 does not classify feasibility as a PHASE ?!

dear all ,

i am wondered why PMBOK 6 ( P 30) classifies the Feasibility in Business case as a pre-project work and shall be done before the project start. where other resources such RITA ver. 9 describes that feasibility could be a separate phase ( page 62 ) ?

regards
Moh

Actually PMBOK 6 does state that feasibility may be treated as separate project or phase. A business case in PMBOK was defined as one form of feasibility; there could be other types of feasibility e.g. engineering etc. PMBOK also describes this.
I do not have Rita's V9, but I have never seen a project start before any feasibility study, but I know that these studies can be a phase of a project or a separate project.
Now a business case can be a whole project or a phase, it depends on how companies may do business, but a business case has to come first, as a feasibility has to come first. You have to justify the idea and determine if its possible before you do it.
So, yes a business case has to be pre-work and can be a separate phase of a project. If that phase does not pan out, the project would be closed.
I hope this helps answer your concern.