Insufficient Information: Too Many Unknowns !

I work with the project team on listing estimating assumptions and indicate a margin of error on estimates where there is low confidence.. If the assumption later proves false I assess the impacts. Procurement delivery lags with new vendors is one example where I use this. The assumptions are logged in my PMP and reviewed regularly.

Michelle, just to leverage your point and glad you brought up a point that seems to have been missed.

Much as I like all the talk about the risks - we still have to plan. We typically do not get to turn down a project just because it the level of uncertainty. In order to plan we make assumptions (that are hopefully risk-based).

In my experience planning does not necessarily fail in the explicit consideration of risk, but in managing the layers of assumptions that were made! It is easy to have contradictory or invalidated assumptions buried in a plan.

I think I am more concerned about the potential internal inconsistent assumptions unwrapping or interacting in strange ways than the relatively discrete risks.