What is the difference between a Feasibility Study and Business Case?

A Business Case is a high-level analysis documenting the problems to be solved, the obvious alternatives to be considered, and the assumptions, constraints, risks, costs, and schedule involved in acquiring and implementing a chosen solution. A Business Case rarely examines the universe of all possible alternatives. Rather, because a Business Case often involves a selection between two or more quantified solutions or paths to a solution, it rarely requires the rigorous analyses that are otherwise needed in instances where the potential universe of solutions has not been previously explored.

A Feasibility Study, on the other hand, takes what a Business Case presents and drills down into much greater detail. A Feasibility Study is actually a two-part process, beginning with a high-level analysis. This first analysis phase starts with the assumption that all possible solutions, including the Status Quo, are on the table. Beginning with a full-blown requirements definition, "As-Is" and "To-Be" descriptions, and the associated gap analysis between them, this first phase works to narrow the universe of options, based on a high-level evaluation of each possible solution in the universe using a set of weighted, pre-defined criteria. The goal of this first phase is to narrow down the potential solutions to the best three to five potential options.

At this point a second and much more detailed phase of the Feasibility Study process begins: the Analysis of Alternatives. This second phase is much more rigorous in its analysis and evaluation. Each of the three to five solutions, including the status quo, now undergo a very detailed, prescriptive evaluation against the requirements of the desired "To-Be" model. The Status Quo is documented, even if it is not selected as one of the three to five best alternatives to be examined because it, at the very least, documents the existing costs and benefits of current operations, providing a baseline against which all other solutions can then be measured. The Analysis of Alternatives is in some ways similar in scope to the selection process used in scoring bidder proposals to a complex procurement, the evaluation criteria look not only score how requirements are, will, or can be met (a much more detailed Gap Analysis using weighted requirements), but also score criteria such as: existing, new and improved capabilities; proven track records and capacity to succeed; transition, training, and applicability to existing tools and skill; risks and risk mitigation; costs; and, most importantly, quantitative and qualitative benefits analysis.

The ultimate goal is to arrive at a solution that will deliver the most comprehensive, functional product, with the least risk of acquisition and implementation, at the least cost, and producing the greatest set of benefits. It will be a solution that, collectively, satisfies the evaluative criteria better than the next potential option, given the organization's stated goals as evidenced by the scoring and weighing criteria used in evaluating each of the alternatives in the Analysis of Alternatives.

A Business Case is useful for lower risk, less costly endeavors, whereas, a Feasibility Study is most often called for when costs, risks, schedule, and the robustness of a chosen solution all are considered substantial and consequential factors critical to success.