I am periodically asked whether a business case should be required for those projects that fall into the "must do" category - projects such as those required to meet regulatory or auditing needs, bring a system up to security or other standards, or migrate off of end-of-life platforms. Why do a business case for these? you might ask. We know we're going to do them, and since there's no incremental business benefit, an ROI calculation is not practically calculated. So why go through the effort?
My view is simple - even without a quantifiable business benefit, the business case analysis helps in three ways:
The business case clarifies the alternatives. There are often multiple ways to accomplish the desired outcome. Evaluating each possible scenario using a standardized methodology clarifies the advantages and disadvantages, cost and time differences, and resource requirement differences in each choice. While a go/no go decision may be preordained, planners will be better prepared to pick the alternative that is least onerous to the organization.
The business case exposes differences in risks. Each alternative will likely have a different risk profile. A seemingly less expensive alternative requiring custom internal development may be more risky - both from cost and benefit perspectives - than a cloud-based COTS alternative with a higher list price. Documenting the risks associated with each alternative, something we recommend in any business case analysis, will point to the optimum solution.