How Serre calculates ROI

Every number in a Serre business case comes from transparent math you can read — formulas with inputs you control. The math is shown, not hidden: the AI helps you draft formulas and writes the narrative around the results, but it never invents or adjusts a number.

From drivers to a total

Each value driver in your case carries a formula — for example:

dispatches_per_month × cost_per_dispatch × deflection_rate × 12

Serre evaluates each driver with the inputs you entered, shows the step-by-step trace, and sums the results into the case's total annual benefit. You can expand any driver to see exactly how its number was produced. There is no black box between an input field and the headline figure.

The headline metrics

On the Calculate step you'll see four numbers:

• Annual benefit — the summed value of all active drivers, per year.
• ROI — return on investment: benefit relative to what the prospect pays (subscription, implementation, training, and ongoing costs over the deal term).
• Payback — how many months until the accumulated benefit covers the investment.
• 3-yr NPV — net present value: the three-year benefit stream minus costs, with future money discounted to today's value.

The investment side is yours to configure: deal term, annual price, implementation cost, training cost, and ongoing cost all live on the Calculate step.

Why you get a range, not just one number

A single-point ROI invites a single question: "says who?" So alongside the expected result, Serre stress-tests the case across the plausible range of each input and reports three outcomes:

• Conservative. Things go worse than expected.
• Expected. The middle of the range.
• Upside. Things go better than expected.

Leading with the conservative number is usually the strongest move in the room: if the case clears the bar in the conservative case, the conversation is over.

A note on credibility

Serre's Val Review step will flag results that are technically correct but rhetorically fragile — for example, an ROI above 1000% reads as un-credible to a CFO even when the math holds. Big numbers are sometimes better presented in benefits-only mode, which the review step lets you toggle.

Related

• What is a value driver?
• Build a business case