Supply And Demand

---
name: supply-and-demand
description: Predict price and quantity changes by analyzing how supply (what producers offer) and demand (what consumers want) interact at market equilibrium
---

# Supply and Demand

## Overview
Supply and demand is the foundational economic model explaining price formation in markets. When demand exceeds supply, prices rise until equilibrium is reached. When supply exceeds demand, prices fall. Understanding these dynamics helps predict market behavior, pricing power, and resource allocation.

## When to Use
- Setting prices for products or services
- Predicting market behavior after policy changes
- Evaluating whether to enter a market
- Understanding why prices fluctuate
- Analyzing competitive dynamics
- Forecasting business impact of supply shocks

## The Process

### Step 1: Map Current Supply and Demand Curves
Identify: How much are producers willing to supply at different prices (supply curve slopes up)? How much are consumers willing to buy at different prices (demand curve slopes down)?

**Example:** Concert tickets: At $500, venue supplies 10,000 seats but only 2,000 buyers. At $50, 20,000 buyers want tickets but venue only supplies 10,000.

### Step 2: Find Equilibrium Price
Equilibrium occurs where supply curve intersects demand curve—the price where quantity supplied equals quantity demanded. No shortage or surplus.

**Example:** Equilibrium: $150 per ticket, 10,000 seats sell, 10,000 buyers purchase. Market clears.

### Step 3: Predict Shift Effects
When demand increases (shift right), price and quantity rise. When supply increases (shift right), price falls but quantity rises. Distinguish shifts (curve moves) from movements along curve (price changes).

**Example:** Famous artist announces retirement (demand shifts right). New equilibrium: $300 per ticket, venue adds second show, 15,000 total sell.

### Step 4: Analyze Elasticity
Price elasticity measures responsiveness. Inelastic demand (necessities): price changes don't reduce quantity much. Elastic demand (luxuries): price increases kill demand.

**Example:** Insulin (inelastic): 20% price increase → 5% quantity drop. Concert tickets (elastic): 20% increase → 40% quantity drop.

### Step 5: Apply to Business Decisions
Use supply/demand analysis for pricing, capacity planning, market entry, competitive strategy.

**Example:** SaaS company sees elastic demand. Instead of raising prices 20% (loses 40% customers = net revenue loss), increases value to shift demand right, then raises prices 10%.

## Example Application

**Situation:** Ride-sharing company deciding surge pricing strategy during peak hours.

**Application:**
- **Supply**: Fixed driver availability short-term
- **Demand**: Spikes 300% Friday nights
- **Without surge**: Price stays $10. Demand (15,000 rides) >> Supply (5,000 drivers) = 10,000 unserved riders, angry customers
- **With surge**: Price increases to $25. Demand drops to 7,000 rides (elastic). Supply increases to 7,000 drivers (higher pay attracts drivers). Market clears.

**Outcome:** Surge pricing solves shortage, increases driver supply, serves more total riders (7,000 vs 5,000), improves experience.

## Anti-Patterns
- ❌ Ignoring elasticity (assuming demand won't change when you raise prices)
- ❌ Confusing correlation with causation (sales dropped after price cut ≠ price cut caused drop)
- ❌ Assuming supply/demand applies to monopolies (model requires competition)
- ❌ Forgetting substitutes (demand shifts when alternatives become available)
- ❌ Treating all goods as elastic or all as inelastic
- ❌ Ignoring non-price factors (quality, brand, convenience)

## Related
- price-elasticity
- network-effects
- switching-costs
- economies-of-scale
- marginal-utility