Case types and frameworks

#The four archetypes

Nearly every case, across all three firms, is a variation on four underlying question shapes: profitability (a business's profit changed — why, and what to do), market sizing (estimate the size of a market or quantity from first principles, with no lookup available), market entry (should this company enter this new market/geography/segment, and how), and M&A or growth strategy (should this company acquire, partner, or grow organically, and where). Profitability and sizing questions together are reported to make up roughly 60% of cases across MBB firms, though this figure comes from aggregated practitioner sources rather than a firm-published breakdown and should be read as a rough pattern, not a precise share. [Directional]

Two further variants recur but are less universal: operations/cost cases (a narrower profitability variant focused specifically on the cost side) and non-profit or public-sector "impact" cases (lives affected, resource allocation) that swap profit for a stated social or policy objective as the optimization target. [Directional]

#What a framework actually is — and isn't

A framework in this context is a starting scaffold for breaking a messy problem into MECE (mutually exclusive, collectively exhaustive) buckets — the standard profitability tree splits into revenue and cost; a market-entry scaffold might split into market attractiveness, competitive position, and financial/operational feasibility. These scaffolds exist because some first pass at structure is unavoidable — nobody can hold an unstructured problem in working memory and reason about it well. [Directional]

The failure mode this course keeps naming, because every source surveyed names it independently, is treating a memorized framework as the deliverable rather than the starting point. Interviewer-facing guidance and instructor writeups converge on the same warning: presenting a generic, unmodified textbook structure (a rote profitability tree, an unmodified Porter's Five Forces) for every case reads immediately as pattern-matching rather than thinking, and experienced interviewers are specifically trained to notice it. [Directional] Poor or generic structure — not math errors, not communication style — is repeatedly cited as the single largest driver of case-interview rejections. [Directional] One frequently repeated claim goes further, stating that roughly half of all McKinsey cases cannot be solved with a standard framework at all; this figure traces to a single source with no stated methodology behind it, and this course flags it as unverifiable rather than repeating it as fact — the underlying point (some cases require a genuinely custom structure with no clean off-the-shelf match) is corroborated by the broader pattern above even though the specific "50%" is not. [Speculative]

#The actual skill: building a live, tailored issue tree

What separates a passing structure from a failing one is not which named framework a candidate recalls — it's whether the candidate can take a generic starting scaffold and bend it to the specific client's specific problem within the first two minutes of hearing it, out loud, while the interviewer watches the reasoning happen. A profitability case about a regional airline and a profitability case about a SaaS company should not produce the same tree, even though both start from "revenue minus cost" — the airline tree needs load factor and fuel-cost buckets; the SaaS tree needs churn and customer-acquisition-cost buckets. A candidate who forces the same four-box template onto both is demonstrating memorization, not the analytical skill the interview exists to test (see Why case interviews exist).

#How to actually practice this

The productive practice loop is not "learn seven frameworks and drill matching a case to the right one." It's: internalize the two or three genuinely universal starting shapes (a profit-driver split, a company/customer/competitor lens, an internal/external factors split) as raw material, then drill building a fresh, case-specific tree from that raw material against a wide variety of prompts, out loud, under time pressure, with someone giving real feedback on whether the tree was actually tailored or just relabeled. Mental math and structuring drills covers the specific drilling method; the resource comparison in The resource landscape flags which prep platforms actually train this custom-structuring skill versus which ones mostly teach framework recall.