🚚 Supply Chain Management

Definition: The management of the flow of goods and services, including all processes that transform raw materials into final products, from supplier to end customer.

Key courses: HBS TOM, Wharton OIDD, MIT SCM (bonus)

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🗺️ The Supply Chain Structure

flowchart TD
    RM[📦 Raw Material Suppliers] -->|Materials + Info| CM[⚙️ Component Manufacturers]
    CM -->|Materials + Info| MA[🏭 Manufacturers / Assemblers]
    MA -->|Goods + Info| DW[🚛 Distributors / Wholesalers]
    DW -->|Goods + Info| RT[🏬 Retailers / DTC]
    RT -->|Products| EC[🛒 End Customers]
    
    %% Reverse flows (money/demand)
    EC -.->|Demand + Capital| DW
    DW -.->|Orders + Capital| MA
    MA -.->|Orders + Capital| RM

Each arrow represents flows of: Materials + Information + Finances

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🔑 Core Trade-Off: Efficiency vs. Responsiveness

Strategy	Efficiency Focus	Responsiveness Focus
Goal	Lowest cost	React fast to demand
Supply	Reliable, high-volume suppliers	Flexible, redundant suppliers
Inventory	Minimal (JIT)	Buffer stock
Lead time	Acceptable longer leads	Short, fast leads
Best for	Stable, predictable demand	Volatile, fashion, seasonal
Example	Toyota (stable products)	Zara (fast fashion)

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📦 Inventory Management

Economic Order Quantity (EOQ)

$EOQ=\sqrt{\frac{2DS}{H}}$

Variable	Meaning
D	Annual demand
S	Ordering cost per order
H	Holding cost per unit per year

EOQ finds the order size that minimizes total inventory cost (ordering cost + holding cost).

Safety Stock

$SS=z\times {\sigma }_{demand}\times \sqrt{LT}$

• z = service level z-score (e.g., z=1.65 for 95%)
• σ_demand = standard deviation of demand
• LT = lead time

Reorder Point = Lead Time Demand + Safety Stock

Just-In-Time (JIT)

• Zero inventory philosophy from Toyota
• Receive materials only when needed in production
• Requires tight supplier relationships and predictable demand
• Risk: Supply disruptions (COVID-19 exposed JIT vulnerabilities)

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🌊 The Bullwhip Effect

Definition: Small fluctuations in consumer demand cause amplified swings in orders further up the supply chain.

Consumer buys 100 units → Retailer orders 120 → Wholesaler orders 150 → Manufacturer orders 200

Causes:

• Demand forecast errors
• Order batching (ordering weekly instead of daily)
• Price fluctuations (forward buying)
• Rationing game (shortage hoarding)

Solutions:

• Vendor-Managed Inventory (VMI)
• Sharing POS data with suppliers (CPFR)
• Everyday low pricing (eliminate promotions that cause hoarding)
• EDI / real-time information sharing

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🌍 Global Supply Chain Strategy

Offshoring vs. Reshoring vs. Nearshoring

Strategy	Definition	Trend
Offshoring	Production in low-cost distant country	Declining post-COVID
Reshoring	Bringing production home	Growing (chips, pharma)
Nearshoring	Moving to nearby countries	Growing (Mexico for US)

Drivers of reshoring (post-2020):

• COVID supply chain disruptions
• Geopolitical risk (China tension)
• Rising labor costs in Asia
• “Made in USA” brand value
• Inflation Reduction Act incentives

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🔄 Case: Zara’s Supply Chain Advantage

Zara (Inditex) reinvented fashion supply chains:

Traditional Retailer	Zara
Plan 6–12 months ahead	Design to shelf in 2–4 weeks
Large batch orders	Small batch orders
Low cost manufacturing	Spain/Portugal manufacturing (near)
Rarely stockouts managed	Intentional scarcity
Price markdowns	Almost no markdowns

Result: Zara carries 1/10th the inventory of peers, at higher margins, with 30% less waste.

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🔗 Connected Concepts

• Lean Manufacturing — Toyota’s supply chain philosophy
• Theory of Constraints — Bottleneck management in supply
• Bullwhip Effect — Demand amplification problem
• Make vs. Buy Decision — Vertical integration choice
• Global Supply Chain Risk — Resilience planning

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← ⚙️ Operations MOC | Related: Lean Manufacturing · Theory of Constraints · Bullwhip Effect