Portfolio project selection and in particular portfolio decision analysis (DA) approaches at their most basic rely on a simple economic notion – rank investments in order of value gained per dollar spent and fund them in this order until the budget is spent. But the quality of the recommendations generated by such an approach is only as good as the quality of the assumptions about projects that are used. In this paper we consider how much effort is worth expending to improve definition of alternatives at the project level.
Keisler, Jeffrey, "The Value of Refining Buy-up Alternatives for Portfolio Decision Analysis" (2010). College of Management Working Papers and Reports. 8.