A business case should survive implementation.

A convincing proposal explains the opportunity. A useful business case also explains the conditions under which the opportunity can be delivered.

Define the decision before developing the model

Before comparing scenarios, establish what is being decided. Is the organisation considering an investment, selecting a delivery model, seeking financing, or deciding whether to proceed to the next preparation stage? Different decisions require different levels of evidence.

The project definition should be clear enough to identify its intended users, outputs, delivery responsibilities, and expected costs. The World Bank’s PPP Reference Guide treats this definition as a foundation for appraisal and considers feasibility across technical, legal, environmental, and social dimensions.

Give important assumptions an owner

A model can contain a precise number while the underlying commercial assumption remains uncertain. Demand, pricing, operating costs, implementation dates, and financing expectations should each have an identifiable source and a person responsible for explaining the assumption.

It is useful to distinguish information already supported by evidence from assumptions that still need testing. Sensitivity analysis can then focus on the variables that could change the decision, rather than creating scenarios that look different but rely on the same unresolved premise.

Connect the case to the delivery arrangements

Consider who is responsible for each significant step, what approvals are required, and how the contractual and institutional arrangements support delivery. A project schedule is more useful when its dependencies are visible. A financial forecast is more useful when the rights and responsibilities behind its cash flows are understood.

For infrastructure and public projects, the distinction between economic benefit and financial return also deserves attention. A project can create benefits for society that are different from the revenue available to the project itself. Those questions need to be assessed on their respective terms.

Make the next stage explicit

The conclusion should identify the decision supported by the available evidence and the work that remains necessary. This may involve refining a structure, testing assumptions, developing procurement documents, or confirming implementation responsibilities.

A useful business case leaves the decision-maker with a clear view of the opportunity, the conditions for proceeding, and the practical steps required to move forward.

This perspective provides general information and does not constitute legal or tax advice. The facts and applicable requirements need to be assessed for each arrangement.