ケース面接対策
一部の MBA インタビューで採用される。コンサル系インタビューに似た形式。
ケース面接の対象
MBA で出題される可能性
- Stanford GSB（ケース寄りの質問）
- 一部のヨーロッパ MBA
- コンサル業界目標を明示する場合
- ポストMBA のキャリア面接（McKinsey, BCG, Bain 等）
純粋なケース面接よりは「ビジネス思考」を確認するスタイル
- 計算精度より思考プロセス重視
- 構造化能力の確認
典型的な質問例
Market Sizing
- "How many smartphones are sold in Japan per year?"
- "What's the market size of structured products in Japan?"
Profitability
- "Why is [Company X] less profitable than [Company Y]?"
- "How would you increase MonotaRO's profit margin?"
Strategy
- "Should [Company X] enter the Japanese market?"
- "How should a Tokyo-based fintech expand into Southeast Asia?"
Hypothetical
- "If you were CEO of MonotaRO, what would you do differently?"
ケース面接の解法フレーム
Step 1: Restate（質問の再確認）
- "Just to make sure I understand correctly, you're asking..."
- 確認することで思考時間を稼ぐ
Step 2: Clarifying Questions（明確化質問）
- "Before I dive in, can I ask a few clarifying questions?"
- 範囲・制約・目的の確認
Step 3: Structure（構造化）
- "Let me think about this in three parts: A, B, and C."
- 構造を最初に共有
Step 4: Analysis（分析）
- 各セクションを順番に
- 数値が必要なら計算
Step 5: Recommendation（推奨）
- "Based on this analysis, my recommendation is..."
- 結論 + 理由
主要フレームワーク
Profitability Framework
Profit = Revenue - Cost
= (Volume × Price) - (Fixed Cost + Variable Cost)
Market Sizing
Top-down: 全体 → 推定割合 → 答え
Bottom-up: 単位 × 数 = 答え
4P Framework（Marketing）
- Product
- Price
- Place
- Promotion
Porter's 5 Forces
- Competitive Rivalry
- Bargaining Power of Buyers
- Bargaining Power of Suppliers
- Threat of New Entrants
- Threat of Substitutes
3C Framework
- Company
- Customer
- Competition
SWOT
- Strengths / Weaknesses / Opportunities / Threats
ケース例: "How would you increase MonotaRO's profit margin?"
解法
Step 1: Restate
"You'd like me to suggest ways to improve MonotaRO's profitability, specifically the margin. Let me think about this in three categories: revenue per customer, cost optimization, and product mix."
Step 2: Clarifying
"A few clarifying questions: are we focused on short-term (next year) or long-term (3-5 years)? Are there any segments we should particularly focus on?"
Step 3: Structure
"Three areas:
- Revenue: increase ARPU through bundling, upselling, premium tiers
- Cost: optimize logistics, automate operations, vendor consolidation
- Product Mix: shift toward higher-margin private brand products"
Step 4: Analysis
"Let me dive into each. For Revenue: MonotaRO has 9M+ business customers. Average order frequency is roughly... [specific data]..." [continues with analysis]
Step 5: Recommendation
"If I had to prioritize, I would focus on Product Mix first—shifting to higher-margin PB products has the highest leverage with lowest implementation risk."
ケース面接 練習方法
Phase 1: 基礎理解
- "Case in Point" by Marc Cosentino（標準教材）
- McKinsey / BCG の公式練習問題
Phase 2: 模擬ケース
- 友人・コンサル経験者と
- 録音 → 自己評価
Phase 3: 業界特化
- Fintech / B2B EC / 産業 DX のケース
- 自分のドメインで深掘り
このプロファイル向け Tips
強み活用
- ファイナンス分析: CMA 知識
- データ分析: BigQuery / dbt 経験
- マーケティング: 仕組債マーケ + MonotaRO 販促
- B2B EC: 直接的な業界知見
注意点
- 過度に専門用語を使わない
- 一般化された ビジネス用語で説明
- 自分の業界経験を「武器」として活用
ケース面接 想定質問 と 短回答
"Estimate Japan's structured products market"
"Japan has about 50 trillion yen in retail investment assets. Structured products are roughly 10% of that, so about 5 trillion yen. Annually, new issuance is about 10-15% of outstanding, so 500-750 billion yen per year. This breaks down across major securities firms, with about 20-25% market share each for the top 4-5 firms."
"Why is MonotaRO more profitable than competitors?"
"Three structural advantages: (1) digital-first platform with low cost-to-serve compared to traditional distributors, (2) PB (private brand) penetration that's higher than industry average, and (3) data-driven inventory optimization that reduces working capital tied up in stock."
Mock Case Practice Log
| 日付 | ケース | パートナー | 自己評価 (1-10) | フィードバック |
|---|---|---|---|---|
| YYYY-MM-DD | _____ | _____ | _____ | _____ |
| YYYY-MM-DD | _____ | _____ | _____ | _____ |
学習リソース
推奨書籍
- "Case in Point" by Marc Cosentino
- "Case Interview Secrets" by Victor Cheng
- "The McKinsey Way" by Ethan Rasiel
オンライン
- McKinsey の公式練習問題
- BCG / Bain の公式 Case Practice
- PrepLounge（ケース面接マッチングプラットフォーム）
YouTube
- "Management Consulted" チャンネル
- "MBA Crystal Ball" Case Tutorials