Separate revenue, variable costs and fixed costs. Compare acquisition cost with customer contribution over a consistent period. Do not treat projected LTV as fact: show scenarios and unknown inputs.
RA LAB practical guide · published 16 October 2026 · based on the library’s GRI / GTM sources.
GOAL
Understand contribution per sale and test acquisition economics.
VALUABLE FINAL DELIVERABLE
A revenue, variable cost, CAC and scenario worksheet with explicit assumptions.
From problem to decision
1. Define the unit
A transaction, a customer and a subscription month are different units. Choose one unit and a consistent period.
Unit, period, data source and missing inputs.
2. Calculate contribution
Contribution per unit equals revenue per unit minus variable costs. Include payment, service, returns and other costs that grow with sales. This is not net profit.
Revenue, variable costs, contribution and exclusions.
3. Check acquisition
CAC equals acquisition spend divided by new customers over a consistent period. State the cost scope. Subscription payback depends on retention and monthly contribution.
Spend, new customers, CAC, contribution over the period and retention scenarios.
4. Choose a change
Test pricing, cost and retention scenarios. Set a minimum acceptable outcome and validate it using actual data.
Which input changes, how do we measure it, and when do we decide?
How to judge whether it helped
You should leave with a document that supports a decision and a next action. Completing steps does not guarantee a commercial result. Measure the chosen change separately over an agreed period. If evidence is missing, state that and plan how to collect it.
How this differs from S01–S13
This is a user route for a specific problem. The GRI AI research stages S01–S13 and the 13-week programme remain in the library as separate methodological work. This route is not a validated GRI diagnostic scale.
Your route0 / 4 · 0%
Completed 0 · remaining 4
Next action: Define the unitThe percentage measures completed steps, not proven business growth.
PRACTICE / 1
Define the unit
A transaction, a customer and a subscription month are different units. Choose one unit and a consistent period.
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