In-Depth Notes on Taxes, Subsidies, Surplus, and Market Analysis

Tax Impact on Demand:
- A tax increases prices for consumers, causing demand to shift left (decrease).
- New equilibrium results in a lower quantity and price received by sellers, while consumers pay a higher price.
Tax Impact on Supply:
- Taxes increase sellers' costs, leading to a decrease in supply.
- Supply curve shifts leftward, resulting in higher prices for consumers and lower prices for sellers.
Price Wedge Created by Tax:
- Tax introduces a disparity between consumer and producer prices:
- Consumers pay more, producers receive less,
- Overall market quantity sold decreases.

Prices:
- Consumers face a higher price, producers receive a lower price; the gap represents the tax.
Tax Per Unit:
- Represented as the vertical gap between supply and demand curves.
Quantity Effects:
- Tax leads to a reduction in quantity sold as fewer units traded.
Government Revenue Generated from Tax:
- Revenue = Tax per unit × Quantity sold, visualized as a rectangle on the graph.
Deadweight Loss (DWL):
- DWL occurs due to the total surplus loss from reduced quantities traded.
- Represented as a triangle between old and new equilibrium points on the graph.

Tax Incidence:
- Describes how tax burden is shared between consumers and producers:
- The inelastic side bears more burden (less responsive to price changes).
DWL in Different Scenarios:
- Elastic demand & supply: Equal burden and lower DWL due to market flexibility.
- Inelastic demand & supply: Equal burden and higher DWL due to rigidity.
- Elastic demand & inelastic supply: Producers carry more tax burden.
- Inelastic demand & elastic supply: Consumers take on more burden.

Tax on Input Goods:
- Leads to a decrease in supply for related goods, driving up prices.
Tax on Substitute Goods:
- Increases demand for untaxed goods, raising their price and quantity.
Tax on Complement Goods:
- Decreases demand for related goods, lowering price and quantity.

Effect of Subsidies on Demand:
- Subsidies lower effective prices for consumers, shifting the demand curve right.
Effect of Subsidies on Supply:
- Reduces production costs, causing the supply curve to shift right.
Price Wedge from Subsidies:
- Creates a wedge where consumers pay less and producers receive more.

Prices Under Subsidies:
- Consumers pay a lower price, while producers receive a higher price.
Subsidy Quantification:
- Subsidy magnitudes represented as a vertical gap on graphs; government financing reflects the rectangle between consumer and producer prices.
DWL from Subsidies:
- Occurs due to overproduction, representing lost total surplus.

Consumer Surplus (CS):
- Difference between consumers' willingness to pay (WTP) and the price paid up to the quantity purchased.
- Graphically represented as the area below the demand curve and above the price line.
Producer Surplus (PS):
- Difference between the price received and marginal costs for producers up to the quantity sold.
- Illustrated above the supply curve and below the price line.
Total Surplus (TS):
- Sum of CS and PS representing total welfare in the market.

Pareto Efficiency:
- No individual can be better without another being worse off.
Kaldor-Hicks Efficiency:
- Gains from trade exceed losses even if not everyone benefits equally.
Productive Efficiency:
- Firms achieve maximum output at minimized costs.

Externalities:
- Negative externalities lead to overproduction and resulting deadweight loss.
- Positive externalities cause underproduction.
Public Goods:
- Issues arise due to the free-rider problem where goods are non-excludable and non-rivalrous.
Monopolies:
- Result in reduced output and higher prices, resulting in inefficiency and DWL.