Diagnosis & Opportunity Sizing
Diagnosis and opportunity sizing is the discipline of reading a fully instrumented funnel end-to-end, isolating the specific stages where revenue is leaking, and quantifying the dollar value of closing each leak so investment goes to the highest-return lever. Without a rigorous diagnosis, growth budget is allocated to the loudest channel, not the most valuable one.
- Diagnosis is quantitative. Every candidate opportunity is sized in expected contribution margin, not in vibes.
- The output is a ranked list of interventions with expected lift, required traffic, and payback period.
- Opportunity sizing sets the ceiling on how much time and budget an experiment is worth.
- Bad diagnosis is why most growth teams run the same tests on the same pages for years.
Where does this stage earn its keep?
Growth teams ship activity, not compounding. They optimize the page they already trust instead of the stage that actually leaks. Without a warehouse-grounded diagnosis, teams underinvest in the highest-value fix and overinvest in the most-visible one.
Terms this stage depends on.
The estimated contribution-margin gain from closing a specific funnel leak, given current traffic, current conversion rate, and a realistic assumption about achievable lift.
A stage in the customer journey where drop-off rate is significantly worse than the benchmark or the historical mean for the same segment.
Opportunity size multiplied by the probability of the test winning at the required significance, minus the fully loaded cost of running the test.
What changes when this stage is done properly.
Illustrative comparison of diagnosis modes.
| Metric | Gut-driven attribution | Fully-instrumented data pipeline |
|---|---|---|
| Prioritization signal | Loudest stakeholder or last quarter's board deck. | Ranked opportunity size in contribution margin. |
| Traffic accounting | Ignored. Tests launch on pages that cannot reach significance. | Required sample size computed before scoping. |
| Lift assumption | Aspirational. | Benchmarked against prior tests on the same funnel stage. |
| Investment decision | Even split across channels. | Concentrated on the top two or three sized opportunities. |
The operational shape of this stage.
- 01Pull the warehouse funnel from first touch to activated customer, segmented by acquisition source, product, and cohort.
- 02Flag every stage where drop-off is materially worse than the segment benchmark.
- 03Size each candidate leak in monthly contribution margin at plausible achievable lift.
- 04Cross-reference sizing against required sample size. Discard opportunities that cannot reach significance in a reasonable cycle.
- 05Deliver a ranked one-page brief. That brief drives the next four to six weeks of hypotheses.
Sizing a checkout leak
A funnel showing 8% lead-to-order at 10,000 monthly leads and $180 contribution margin per order is producing roughly $144,000 per month. Closing the leak from 8% to 12% represents an additional $72,000 in monthly contribution margin. That is the opportunity size, and it sets the ceiling on how much design, engineering, and paid media rebalance the fix is worth.
Frequently asked about this stage.
What is opportunity sizing?
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What is opportunity sizing?
+How is diagnosis different from a funnel audit?
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How is diagnosis different from a funnel audit?
+See this stage run against your numbers.
A 30-minute Growth Audit. You leave with two or three specific findings, whether or not we ever work together.
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