The ROI number doesn't win the deal. The argument does.

In November 2023, a value selling platform analyzed 2,960 opportunities across five B2B SaaS companies. They wanted to know what actually predicted wins. Traditional ROI metrics (payback period, net present value, internal rate of return) did not strongly correlate with deal outcomes.

What did correlate was whether the customer helped build the model.

Customer co-creation of the value model tracked to 3.4x higher odds of winning. Internal collaboration between sales and product tracked to 2.4x higher odds. The number itself was not the variable that moved.

Because a number the vendor produced alone is a vendor claim. And buyers discount vendor claims on sight.

A separate finding reinforces this. Analysis of 100,000 sales presentations, cited by Chris Priemer from Gong's research, associated heavy ROI language with lower close rates. The more a seller leaned on ROI claims, the less the buyer believed them.

The trust problem is structural. Whoever owns the assumptions owns the trust. A business case the seller built in a back room and sent over looks like marketing math. A business case the buyer helped build looks like their analysis.

No. And this is the turn.

The model is what makes co-creation possible. You cannot collaboratively adjust a number that does not exist. You cannot invite challenge on assumptions you never wrote down.

A value model built before the meeting gives the buyer something to react to. Show them the drivers you turned off. Let them change the inputs. Let them see the calculation adjust in real time. A case the buyer has edited is a case the buyer will defend internally.

I wrote about this mechanism earlier this year: the value story you build alone won't survive the economic buyer review. The one you build together has a chance.

Build the model before the meeting. Then open it in the meeting.

Walk the buyer through which value drivers you included and which you excluded. Show the assumptions. Adjust them together. Let them challenge the benchmark numbers. Let them tell you which drivers matter most in their organization.

The output is still a quantified business case. The difference is that the buyer now owns it.

This is not about making the buyer do your work. This is about giving them the tools to do theirs, which is defending your price to their CFO without you in the room.

Should I stop sending ROI calculations?

No. Send quantified business cases. Stop sending numbers the buyer cannot inspect, challenge, or adjust. The difference is between a claim and a model.

What is the difference between a business case and an ROI calculator?

A calculator is inputs-in, number-out. A business case is a structured model with cited assumptions, risk adjustments, and transparent value drivers. Calculators produce numbers. Business cases produce arguments.

Why do buyers distrust vendor numbers?

Because vendors are incentivized to make their products look good. A business case the vendor built alone reads as the vendor making its own case look good. What changes that is transparency: cited equations, market-sourced benchmarks, visible assumptions, and an invitation to challenge any of them.

How do I get a buyer to co-build the case?

Build it first. Show them the output. Then walk them through which drivers are turned on, which are turned off, and what happens if they change the inputs. The model you bring into the room is not the final version. It is the starting point for the conversation.