Excellent question @Citrillion! One important distinction here is that Cost Plus Fixed Fee is not a project delivery method, as noted in another thread (and as you’ve indicated in your post here):
Therefore, Cost Plus Fixed Fee can be used with a delivery method. It is appropriate to use on a project with unknown conditions because of its flexible compensation structure. The question may ask something like: Which project approach is most financially or contractually appropriate when the scope is undefined? - where either a project delivery method or construction contract type could be considered a correct answer.
Depending on the specific circumstances, CMa, CMc, and IPD could all be appropriate for a project with unknown conditions. You’ll want to consider early input (all parties at the table early on), flexible design-phase support, and collaborative arrangements. These three delivery methods help manage scope complexity and change, while Cost Plus Fixed Fee is a contract type that helps manage cost uncertainty.
When answering this type of question on the ARE, note any unique factors in the scenario that might point you in one direction versus another.
Hope this helps!
Kiara Galicinao, AIA, NCARB
Product Coordinator
Black Spectacles