I stop listening when a candidate opens a growth case with the Ansoff Matrix and never puts a dollar on any quadrant. The interviewer is not grading vocabulary. The sheet rewards a ranked list of levers with rough revenue and margin impact, time to cash, and the capability each lever needs. After this piece you should be able to diagnose the growth question in four questions, size five levers on a napkin, and close with two numbers and one flip risk.
Firms publish the same demand in their own practice cases. McKinsey's Electro-Light launch case forces share, break-even, and capability before a go decision. BCG's Med-Lines online practice case opens on how a ferry operator increases revenue, not on framework labels. Bain's FashionCo walks revenue recovery into quantified options. CoachNed is not affiliated with McKinsey, BCG, Bain, or any firm named here.
Ask four questions before you draw a tree
"Grow" is not a structure. Pin these down in under a minute.
- Market growth versus share. If the market is already growing 8% and the client grows 2%, the case is mostly competitive or execution. If the market is flat, you need new volume pools. Same prompt, different first branch.
- Organic versus inorganic. Build, partner, or buy. Inorganic is not a free acceleration button; it trades capital and integration risk for speed. The M&A case framework is the deal math once a buy option survives the ranking.
- Constraint: capital or capability. A client with cash and a weak salesforce is a different problem from a client with a strong brand and a tight balance sheet. Size levers against the binding constraint, not both at once.
- Metric and horizon. Revenue, profit, or share, and by when. Doubling $400M in five years is roughly 15% CAGR. Say the gap out loud before you invent ideas.
If growth stalled, diagnose first with the profitability framework logic (volume, price, mix, cost). If the business is healthy and the board wants more, skip to lever sizing. Naming which mode you are in earns a structure point before any framework name does.
What the sheet rewards instead of Ansoff
Ansoff is a map of product-market risk. Useful as a check that you did not miss a quadrant. Fatal as the recommendation. McKinsey's public growth research on the ten rules of growth stresses coherent pathways and outgrowing peers, not labeling penetration versus diversification. BCG's 2024 revenue-strategy research argues the right path depends on the company's starting point. Bain's work on parenting advantages and growth likewise pushes companies to expand where they can create more value than rivals, which in a case means naming the capability you are betting on.
In the room, put each live lever on four columns: incremental revenue (or profit) at year 3, contribution margin on that revenue, months to meaningful cash, and the capability you must already own or buy. Rank by impact under the client's constraint. That ranking is the structure.
| Lever | Typical time to revenue | Capital intensity | Typical margin effect |
|---|---|---|---|
| Penetration (share, frequency, price) | 3–12 months | Low–medium | Neutral if price/mix; volume often dilutes slightly |
| New segment, same product | 6–18 months | Medium | Often lower than core until mix stabilizes |
| New geography | 12–36 months | High | Dilutive early (setup, channel); core later if transferable |
| Adjacent product | 12–24 months | Medium–high | Wide range; watch cannibalization |
| Acquisition | 6–18 months to own revenue | High | Synergy-dependent; integration can crush margin |
Use this as a prior, then replace every cell with case-specific math. For geography and mode choices, borrow the go/no-go discipline in the market entry framework. For TAM steps inside a lever, use market sizing.
Ned's rule. Never recommend a growth lever you have not sized to within a factor of two. A ranked list with rough dollars beats a perfect Ansoff recital with none.
Worked case: HarborCast picks a growth path
HarborCast makes mid-tier marine electronics for recreational boats in the US. Revenue is $420M, contribution margin 28%, operating margin 11%. The market grows about 3% a year. The CEO wants roughly $150M of incremental annual revenue within three years (~12% CAGR from today's base) and will commit up to $80M of capital. Brand and dealer relationships are strong; the company has never sold outside North America and has no M&A team in-house.
Five levers on the table. Invented company, internally consistent numbers.
| Lever | Year-3 incremental revenue | Year-3 contrib. margin | Months to cash | Capability required | Capital |
|---|---|---|---|---|---|
| Penetration (dealer push + 4% list price) | $55M | 30% | 6 | Sales ops, pricing power | $12M |
| New segment: commercial fishing kits | $40M | 22% | 14 | Product config, new channel | $25M |
| Geography: UK + Nordics | $35M | 18% (y3) | 24 | Local distribution, warranty | $45M |
| Adjacent: boat networking software | $50M | 45% | 20 | Software talent HarborCast lacks | $70M |
| Acquire NavLite (EU chartplotters) | $90M | 25% post-synergy | 12 | Integration; $110M purchase | $110M (over budget) |
Penetration arithmetic. US addressable dealer sell-through on HarborCast's lines is about $1.1B. HarborCast's share is roughly 38% ($420M / $1.1B). A realistic share gain of 3 points on a growing market plus a 4% price lift on the retained base: volume upside ≈ 0.03 × $1.1B ≈ $33M; price uplift ≈ 0.04 × $420M ≈ $17M; total ≈ $50M, round to $55M with mix. Margin improves slightly because price does not carry full COGS.
New segment. Commercial fishing boat installs: 28,000 relevant vessels in the US, $2,200 average kit, 35% attainable penetration in three years under a focused SKU → 28,000 × 0.35 × $2,200 ≈ $22M product, plus $18M accessories and service attach → ~$40M. Margin lower: ruggedization and dealer training.
Geography. UK + Nordics recreational electronics market ~$280M. Credible year-3 share for a new entrant with OEM partners: 12% → ~$34M. Setup costs and dual inventory keep year-3 contribution near 18% until scale.
Adjacent software. 180,000 active HarborCast devices in field; 15% attach at $180/year subscription by year 3 → 27,000 × $180 ≈ $4.9M recurring, too small alone. Hardware gateway sales and professional install push the rest of the $50M, but the firm must hire or buy a software org. Capability is the binding constraint, not TAM.
Acquisition. NavLite does $85M revenue at 24% contribution. Synergies of $5M net and $110M purchase price blow the $80M capital ceiling unless the board expands the check. Speed is real; fit to budget is not.
Recommendation. Lead with penetration for ~$55M at 30% contribution and $12M capital, and pair it with the commercial fishing segment for another ~$40M. Combined ~$95M of the $150M gap on ~$37M capital, leaving room for a later geography pilot. Two numbers that carry the close: $95M year-3 incremental revenue and ~29% blended contribution on that stack. The risk that flips the recommendation: if dealer share gains stall below 1 point after year one, reopen NavLite with a higher capital mandate or a phased earn-out, because organic share then cannot close the gap.
Do not open with "this is market penetration and market development." Open with the ranked table and the close.
Shorter example: a SaaS billing company
LedgerMint sells usage-based billing APIs to mid-market SaaS firms. ARR $90M, net revenue retention 108%, sales capacity constrained. Board wants +$40M ARR in 24 months.
Size three levers only. Expansion (seats and usage tiers) on the existing 420 logos: if NRR rises from 108% to 118%, that is roughly 0.10 × $90M ≈ $9M. New logos at current ACV of $85k with two added AE pods (eight AEs) closing 4 deals each per year → 32 × $85k ≈ $2.7M year one, compounding toward $12M by month 24 with ramps. Acquire a $18M ARR usage-analytics bolt-on at 6× ARR: $108M price, instantly adds revenue but burns the capital the board earmarked for product. Recommendation: fund expansion and one AE pod first ($21M of the gap with existing product capability), then a second pod; defer M&A unless win rates prove the TAM is capped. Same habit as HarborCast: dollars, margin quality (SaaS gross margin stays high on expansion), timing, capability.
Practice this on a timer
Take any growth prompt. Spend two minutes on the four diagnostic questions, eight minutes building a five-row sizing table, and ninety seconds on a close with two numbers and one flip risk. Drill the structure muscle on /drills/structure, then run a full scored case on /start (three typed turns, no account) or the live voice interview on /interview. Everything on CoachNed is open for seven days with no card; then $120 for a recruiting season or $49 a month.
Frequently asked questions
How do you structure a growth strategy case interview?
Clarify metric, gap, horizon, and the binding constraint, then list organic and inorganic levers and size each on revenue, margin, timing, and capability. Rank under the constraint and recommend the top one or two with a flip risk. Framework names are optional; the ranking is not.
Should I always recommend organic growth before M&A?
No. Recommend the lever that hits the target under capital and capability constraints. Acquisition wins when speed or a missing capability dominates and the purchase fits the budget. Organic wins when the core still has share or frequency upside, which matches Bain's published warning not to abandon a fertile core too early in Strategies for Corporate Growth.
Is the Ansoff Matrix still useful in growth cases?
As a completeness check, yes. As the answer, no. Interviewers have heard the four quadrants hundreds of times. They score whether you put rough economics on the options that matter for this client.
What numbers should a growth case recommendation include?
At least incremental revenue or profit at the stated horizon, margin quality on that increment, capital required, and the risk that would change the choice. Two sharp numbers beat a paragraph of adjectives.
How is a growth case different from a market entry case?
Market entry is usually a go/no-go on one geography or segment with mode and payback. Growth strategy ranks several levers, of which entry may be only one. Use the market entry post when the prompt is a single new market; use this sizing habit when the prompt is "how should we grow."
Sources
- Electro-Light | McKinsey Careers — firm practice case on product launch, share, and break-even. Checked 2026-09-24.
- Med-Lines practice case PDF | BCG — firm online practice case on increasing ferry operator revenue. Checked 2026-09-24.
- FashionCo. | Bain & Company — firm practice case moving from revenue decline to quantified recovery options. Checked 2026-09-24.
- The ten rules of growth | McKinsey — published growth research on pathways and outgrowing peers. Checked 2026-09-24.
- Your Revenue Strategy Depends on Your Starting Point | BCG — published growth research on choosing a path from the company's starting position. Checked 2026-09-24.
- Growth Strategy: Identifying Your Parenting Advantages | Bain — published growth research on expanding where the firm can create superior value. Checked 2026-09-24.
- Strategies for Corporate Growth | Bain — published argument that underestimating core potential is a common growth failure. Checked 2026-09-24.