How to build a business case your champion can defend

Somewhere in the account, a VP or a senior director is going to carry this. They sat through the demo. They think the product addresses a real problem. Now they have to explain it to finance, procurement and peers who have never spoken to your team and have no reason to trust your numbers.

That person is your champion. The business case you hand them is either something they can open or something they have to apologize for.

What the room actually evaluates

When your champion walks into a budget review, the room is not re-running your demo. They are looking at the case for spending money. The questions are practical:

• Where do these numbers come from? Can every figure be traced to a formula, an input or a source?
• What happens if the assumptions are wrong? If only part of the projected benefit shows up, does the model show that, or does the slide go blank?
• Whose analysis is this? If the method reads like a sales tool, the champion is stuck defending your wording.

None of those questions is a request for a larger ROI. They are a request for something that can be checked.

Arm the champion with the model

You are not building a business case for your champion so they can recite it. You are building a model they can use to construct the case they are willing to put their name on.

• Give them the model, not a static document. A PDF they cannot change dies in the meeting where someone asks for a different labor rate.
• Make the variables visible. If the model assumes a $75 fully loaded hour and their finance team uses $82, they should be able to change it. Every input they change is an input they now own.
• Show the method, not only the result. If they cannot explain a line, they cannot defend the line.
• Put the conservative case on the page. Do not make them ask for it. It is the answer to "what if this does less than you projected?"
• Let them present it as their analysis. The useful outcome is "I built a model to evaluate this," not "the vendor sent a business case."

That last property is ordinary, and it has a plain description. The case has to answer why this, why now, how much and how sure when you are not in the room. Serre's job is to turn every deal into a defensible case for change, from value logic a person on the selling team has approved. The case is a projection. It is not a result, and it is not a claim that the deal will close.

The biggest number is the fragile one

It is tempting to optimize for the largest ROI. The champion's credibility is what actually walks into the room. If the number cannot be opened, they are the person who brought it.

The useful business case is the one your champion can walk through without you. It is not the one with the largest figure.

Give them transparent math, adjustable inputs and a range that says what it assumes. Value engineering for every seller means that work is not reserved for a specialist who is not in the meeting. No value engineer is required. A person still approves what the company is willing to claim. Approval is a judgment, not a hire.