Microeconomics Review

Microeconomics Overview

  • Definition: Microeconomics studies the economic choices individuals and firms make and how these choices create markets.

  • Example Scenario: An economy that produces food and clothing.

    • Production Possibilities Frontier (PPF): A graphical representation showing the maximum combinations of two goods that can be produced with fixed resources.

Production Possibilities Frontier (PPF)

  • PPF Explained:

    • A PPF shows the maximum possible production combinations for two goods with a fixed resource set.

    • Example data points:

    • Produce 10 units of food and 12 units of clothing.

    • Produce 4 units of food and 12 units of clothing.

  • Graphical Representation:

    • PPF diagram illustrates these combinations with axes representing the amount of food and clothing produced.

Fundamental Economic Principles

Principle 1: Scarce Resources

  • Description: Resources are limited; combinations outside the PPF are unattainable due to insufficient resources.

    • Unattainable combination: Cannot produce 4 units of food and 14 clothing.

Principle 2: Opportunity Cost

  • Definition: The cost of producing a good, measured by the alternative goods that are forgone in its production.

    • Example: On the PPF, if more clothing is produced, less food results as the opportunity cost of producing clothing.

Principle 3: Increasing Opportunity Costs

  • Observation: The opportunity cost of producing one more unit of clothing increases.

    • Example:

    • First, the opportunity cost of producing one additional clothing unit is 0.5 food units.

    • Later, this cost rises to 2 units of food for additional clothing units.

Principle 4: Incentives Matter

  • Description: Decisions are driven by perceived opportunity costs.

    • Example Scenarios:

    • Studying 2 hours translates to opportunity costs like potential work shifts or leisure activities.

    • Public spending (e.g., $1M on a stadium) has opportunity costs considering other public needs like school repairs or taxes.

Principle 5: Inefficiencies Involve Real Costs

  • Efficiency Defined: Points inside the PPF are inefficient since they indicate that more of one or both goods could be produced without sacrificing other goods.

Supply-Demand Model

  • Function: The supply-demand model describes how the price of a good is determined by buyer behaviors and supplier responses.

  • Key Components:

    • Supply: As market prices rise, firms increase their production due to higher marginal costs.

    • Demand: Affected by consumer preferences, income, and the prices of substitutes or complements.

Market Equilibrium

  • Definition: The equilibrium price is the price at which quantity demanded equals quantity supplied.

    • Graph Representation:

    • Equilibrium occurs where the demand and supply curves intersect (Price = P; Quantity = Q).

Shifts in Demand and Supply

  • Movement Along the Curve: Price changes lead to quantity changes but do not shift the curve itself.

  • Shifts of Demand: Influenced by factors like changes in income, tastes, and number of buyers.

  • Shifts of Supply: Influenced by input costs, changes in technology, and weather conditions.

Elasticity

  • Definition: Elasticity measures how responsive the quantity demanded or supplied is to price changes.

  • Types of Elasticities:

    • Elastic Demand: Buyers are highly responsive to price changes (e.g., luxury goods).

    • Inelastic Demand: Buyers are less responsive to price changes (e.g., medicine).

    • Elastic Supply: Sellers can easily adjust output; examples include flexible manufacturing setups.

    • Inelastic Supply: Difficult for sellers to increase output quickly (e.g., limited housing supply).

Factors Influencing Price Elasticity of Demand

  • Substitutes: More substitutes increase elasticity.

  • Time Frame: Demand generally becomes more elastic over time as consumers find alternatives.

    • Examples:

    • Housing market responses to rental changes.

    • Tariff-related supply chain adjustments.

Consumer Theory

Two Influential Factors on Choices

  1. Preferences: Personal enjoyment or suitability of goods.

  2. Constraints: Budgetary limits and good prices.

Utility Function

  • Definition: Utility quantifies satisfaction from consuming goods. It can be represented as: U = U(X, Y; ext{other variables})

    • Indifference Curve: Represents combinations of two goods yielding the same level of utility.

Marginal Rate of Substitution (MRS)

  • Definition: MRS measures the trade-off rate between two goods while maintaining the same utility level.

    • As consumption of one good increases, the willingness to give up units of another good decreases, reflecting diminishing MRS.

Perfect Substitutes and Complements

  • Perfect Substitutes: Identical goods where consumers derive the same benefit (MRS is constant).

  • Perfect Complements: Goods consumed together in fixed ratios (like left and right shoes).

Utility Maximization

  • Budget Constraint:

    • Formula:
      PX imes X + PY imes Y = I

    • Indicates how consumers allocate their income to maximize utility from goods X and Y.

Conditions for Utility Maximization

  1. Spend all income.

  2. MRS equals the price ratio of the goods consumed.

Changes to Budget Constraints

  • Income Effects: An increase in income shifts the budget constraint outward.

  • Price Effects: Price changes of goods pivot the budget line.

    • Example: If prices rise variably, some goods become more expensive relatively.

Consumption Optimization Examples

  • Analyze consumer decisions based on budget constraints in real-world scenarios (e.g., choosing between different brands of gasoline).

Discussion Points

  • Current Events: Use real examples (e.g., prices of eggs, rent) to discuss economic factors affecting price changes.

  • Labor Supply Dynamics: Insights into what might alter labor supply.

Production Functions

  • Definition: Relates inputs to outputs mathematically:
    q = f(K, L)

  • Marginal Product: Refers to the additional output from using an extra unit of input.

Isoquant Curves

  • Isoquant Map: Curves depicting various input combinations yielding the same output.

  • Marginal Rate of Technical Substitution (MRTS): Describes the trade-off between inputs at constant output.

Returns to Scale

  • Definition: Measures output response to proportional changes in all inputs.

  • Types:

    1. Constant returns: Proportional increase in output.

    2. Increasing returns: Output increases more than proportional to input.

    3. Decreasing returns: Output increases less than proportional to input.

Cost Minimization Principle

  • Context: Total cost includes wages and rental rates:
    TC = wL + vK

  • To minimize costs, the ratio of marginal products must equal the price ratio of inputs:
    rac{MPL}{w} = rac{MPK}{v}

  • Economic Profit:
    ext{Profit} = ext{Total Revenues} - ext{Total Costs} = Pq - wL - vK

Short Run vs Long Run Costs

  • Short Run: Some inputs fixed; costs are not minimized.

  • Long Run: All inputs are variable.

  • Fixed Costs: Costs that do not change with output levels.

  • Variable Costs: Costs that vary directly with output levels.

Profit Maximization Strategy

  • Firms determine output levels to maximize profits with: rac{d ext{Profit}}{dq} = 0

    • This operates under the condition that marginal revenues equal marginal costs.

  • Decision Rule: When marginal revenue equals marginal cost, profits are maximized.

Housing Market Dynamics

  • Inflation's Impact: Regulatory constraints on construction may cause housing supply to be inelastic leading to price increases amidst rising demand.