McKinsey, Bain, BCG — consulting case interviews demand structured problem-solving under pressure. Profitability cases, market entry, M&A, capacity expansion. PhantomCode runs you through case frameworks, mental math drills, and PEI behavioral, all with AI grading.
The four canonical case types account for ~80% of MBB cases. PhantomCode drills you through profit-tree decomposition, market-entry checklists, M&A synergy frameworks, and capacity expansion analysis.
Cases require fast arithmetic without a calculator. 14 × 87, 3.7M ÷ 0.42, percentage growth from base to target. The AI runs timed mental math drills calibrated to MBB superday speed.
“How big is the global market for X?” Two approaches: top-down (start from population, segment) or bottom-up (start from a single unit, scale up). The AI helps you pick the right one fast.
Personal Experience Interview — McKinsey’s structured behavioral. Leadership, entrepreneurial-drive, personal-impact stories. STAR-format but with consulting-specific framing.
Strong consulting answers lead with a hypothesis. ‘I think the profit problem is on the revenue side because X. Let me test that.’ The AI grades whether your structure is hypothesis-led vs framework-recital.
Most virtual case rounds are recorded. The AI’s window stays out of the recording. You can run case-framework recall in real time without it appearing in the playback.
MBB cases come in roughly four flavors. Recognizing which one you’re in lets you load the right framework fast.
‘Our client’s profits dropped 15% YoY. Diagnose the issue.’
For MBB-tier targets: 6-12 weeks of focused prep is typical. The variable is case volume (need ~30-50 full mock cases) and PEI quality (1-2 weeks alone to nail the three stories). For tier-2 consulting firms: 4-6 weeks is often enough.
Profitability cases are the most common at MBB — they show up in ~40% of cases. Market entry is ~25%. M&A and capacity each ~15-20%. Drill profitability hardest; it's also the easiest framework to learn well.
Candidate-side prep with AI is standard. For virtual case interviews, PhantomCode is invisible to Zoom recording. Use it for framework recall and math verification. The interactive nature of cases means AI assistance is harder to use covertly than in unidirectional Q&A interviews, but it still helps with sub-second framework loading.
Framework-recital without hypothesis. Strong candidates lead with a hypothesis and structure the case to test it. Weak candidates recite a framework (profit tree, 4Ps, Porter's 5 Forces) without committing to a direction. Interviewers can tell the difference within 90 seconds.
Important enough that getting it wrong fails the case. MBB-tier candidates can do mental arithmetic at speed without a calculator. Drill specifically: 14 × 87, 3.7M ÷ 0.42, percentage growth, breakeven calculations. PhantomCode includes a mental-math drill mode.
Profitability, market entry, M&A, capacity cases with hypothesis-led grading and mental math timing.
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