Consumer + Producer surplus

Definition of Surplus: Consumer surplus is the difference between what consumers are willing to pay for a good or service versus what they actually pay. Producer surplus is the difference between what producers are willing to sell a good for versus what they actually receive.
Market Equilibrium: The point where supply equals demand, resulting in maximized social surplus. This equilibrium is considered the most efficient market operating point as both consumer and producer surplus are maximized.

Consumer Surplus:
- Located above the equilibrium price and below the demand curve.
- Represents the maximum price consumers would be willing to pay compared to the market price.
Producer Surplus:
- Located below the equilibrium price and above the supply curve.
- Represents the difference between what producers are willing to sell for and the market price received.

When the market does not operate at equilibrium, there is a welfare loss, which means that the total surplus (sum of consumer and producer surplus) is not maximized.
Welfare Loss: Can occur if either surplus is diminished. It affects the whole community rather than just producers or consumers individually.
Example of Price Impacts:
- If the market price is set too low, consumers are willing to buy more (quantified as $Qc$) than what producers are willing to provide at that price (quantified as $Q1$).
- Thus, the welfare loss results from not being able to produce or consume the desired quantities.

Government can intervened in markets through:
1. Taxation: Generates revenue for the government and can alter market behavior.
2. Subsidies: Provide financial support to producers or consumers, impacting supply and demand.
3. Price Controls: Can be either price ceilings or price floors to protect consumers or producers; often results in unintended consequences.

Types of Taxes:
- Direct Taxes: Collected directly from individuals and businesses (e.g., income tax).
- Indirect Taxes: Imposed on goods and services; collected from suppliers but passed onto consumers.
- Examples include specific taxes (fixed amount per unit) and ad valorem taxes (percentage of price).

Consumer Burden: A higher burden of taxes is seen on consumers when demand for a product is inelastic; they pay a larger portion of the tax.
Producer Burden: When demand is elastic, producers bear a larger share of the tax burden as they cannot raise prices excessively without losing customers.

Ad Valorem Tax:
- Calculated as a percentage of the price
- For instance, a 10% tax on an item costing £10 results in a tax of £1, while the same tax on an item costing £20 results in £2.
Specific Tax:
- A fixed amount regardless of the price, such as a £2 tax per unit sold.

Graphical Representation:
- Specific taxes appear as a parallel upward shift in the supply curve because they add fixed costs per unit to the producers.
- The vertical distance between the original and new supply curves indicates the tax amount per unit.
Effect of Ad Valorem Taxes:
- Result in a non-parallel shift since the tax amount increases with higher prices.

Total tax revenue can be calculated by multiplying the tax per unit by the total quantity sold after tax. If the total output decreases after a tax is imposed, total revenue impacts both producers and government revenue negatively.

Represented in diagrams showing the reduction in overall economic efficiency when taxes alter equilibrium prices and quantities. Calculations include:
- The area of the triangle formed between the supply and demand curves to express the lost efficiency due to taxes.