Economics Fundamentals: Chapter 1-8 Vocabulary (Notes)

Economics: Key Concepts and Examples (Comprehensive Notes)

Overview: What is economics?

  • Economics is the study of decision making under scarcity.
  • It covers how individuals, firms, governments, and societies allocate limited resources (money, time, talents) to satisfy wants.
  • The discipline considers both financial decisions (stocks, bonds, budgets) and broader decision making in markets and institutions.
  • Central framing: decisions happen under scarcity and should be rational and purposeful to maximize satisfaction (utility).
  • The course emphasizes decision making, not only GDP or unemployment figures; economics is a tool for thinking about choices in all areas of life.

Core premises: scarcity, resources, and rationality

  • Scarcity and limited resources drive all decisions.
    • Resources include money, time, talents, skills, opportunities.
    • Even high earners (e.g., Bezos) face limits; resources are finite.
  • Rationality and purposeful behavior guide choices.
    • People try to maximize perceived benefits (utility) given constraints.
  • Utility and satisfaction: outcomes of decisions.
    • Utility is the measure of satisfaction or benefit from a choice.
    • Utility is the driver of economic decisions under scarcity.
  • The two core decisions you’ll focus on: conscious, deliberate choices about how to allocate scarce resources to maximize utility.
  • The Socratic method used in class: questions to elicit reasoning and understanding.
  • Decision making is not just about money; time and talents are key resources too.

Key concepts: utility, scarcity, and rational choice

  • Utility (U): the satisfaction obtained from a choice or bundle of goods.
  • Total Utility (TU): the overall level of satisfaction from consuming a quantity of a good or bundle.
  • Marginal Utility (MU): the change in total utility from consuming an additional unit of a good.
    • Formula: MUn=TU(n)−TU(n−1)MU_n = TU(n) - TU(n-1) or MU = rac{d(TU)}{dQ} in continuous terms.
  • Diminishing marginal utility: marginal utility tends to decrease as more of a good is consumed.
    • Example: first sandwich provides high satisfaction; second yields less; the fourth may even cause disutility (e.g., feeling sick).
    • Illustration: MU1 > MU2 > MU3 > MU4 (often turning TU upward with decreasing increments).
  • Total utility vs. marginal utility: TU is the cumulative satisfaction; MU measures the incremental gain from each additional unit.
  • Practical implication: people allocate resources to maximize total utility; they compare marginal benefits to marginal costs across options.
  • When considering multiple resources (money, time, talent), decisions maximize utility across the entire bundle, not just money spent.

The decision framework: scarcity, rationality, and utility optimization

  • Under scarcity, individuals must allocate limited resources to obtain the greatest overall benefit.
  • Rationality and purposeful behavior imply decisions are made to maximize utility given constraints.
  • Economics is a decision-making toolkit: learn to think critically about how choices are made, not just what is bought or sold.
  • Ethical considerations can be integrated: economics informs about incentives and trade-offs, but normative judgments may require separate ethical reasoning.

Everyday illustrations: practice problems and intuition

  • How many daily decisions? Roughly around 30,000.
    • Only a few thousand are conscious; perhaps a couple hundred are truly deliberate decisions.
  • Example: a golfer’s practice hours (30 vs. 40 vs. 50 hours):
    • Initially, increasing hours raises productivity and utility, but marginal gains decline with time (diminishing MU).
    • After a point (e.g., 40 or 50 hours), further increases may yield smaller improvements and higher fatigue, reducing marginal benefit.
  • The role of emotions and memory: provocative or emotional examples may help fix concepts in memory, though they can be controversial.

The “sandwich” illustration: total and marginal utility in a budget context

  • Setup: one food item (sandwich) with a price and a simple budget constraint.
  • Example values:
    • Budget I = $120
    • Price per sandwich p = $20
    • Suppose you buy 0 to 6 sandwiches; maximum is 6 sandwiches (6 × $20 = $120).
  • Utility discussion: as you consume more sandwiches, TU increases but MU declines (first sandwich provides the most utility; subsequent sandwiches provide progressively less; the fourth could cause disutility if you overeat).
  • Takeaway: consumers choose the quantity that maximizes their total utility given their budget; additionally, they may substitute a different good (e.g., iced tea) if it provides a better MU per dollar.

Budget constraint and trade-offs: two goods example

  • Setup: two goods, A and B, with prices and a fixed income.
    • Example: price of A is $20, price of B is $10, income I = $120.
  • Budget constraint equation:
    20A+10B=12020A + 10B = 120
  • Solving for B as a function of A:
    B = rac{120 - 20A}{10} = 12 - 2A
  • Feasible (attainable) bundles lie on or under the budget line; the unattainable region is outside the line, denoted as L=extunattainableL = ext{unattainable}.
  • Feasible combinations along the line include:
    • (A,B) ∈ {(6,0), (5,2), (4,4), (3,6), (2,8), (1,10), (0,12)}
  • Intuition:
    • The budget line shows all combinations you can afford with given income and prices.
    • Moving along the line represents trade-offs: more of A means less of B and vice versa.
  • Shifts of the budget line:
    • If income increases, the line shifts to the right (more total goods affordable).
    • If prices change, the slope changes (the rate at which you can substitute between A and B changes).
  • Key takeaway: decision making under budget constraints involves trade-offs and the optimization of utility given the feasible set.

Demand, supply, and price effects: what drives purchases

  • In economics, price changes typically affect quantity demanded or supplied (movement along the curve).
  • Two key lines to remember conceptually:
    • Demand curve: usually downward-sloping, showing quantity demanded rising as price falls.
    • Supply curve: usually upward-sloping, showing quantity supplied rising as price rises.
  • Extreme cases and lines on graphs:
    • Vertical demand (or supply) line: quantity demanded (or supplied) does not change with price.
    • This is a case of an infinite or undefined slope depending on how you view the axes.
    • Horizontal line: price remains fixed while quantity changes minimally (highly elastic or inelastic in specific contexts).
  • Thought experiment: essential goods where price changes do not readily affect demand (e.g., need for a life-saving resource like a heart) can produce a near-vertical demand curve (MU/price signals are weak for reducing quantity).
  • In the organ market thought experiment:
    • If organs were tradable, the price would fall as supply increases, and access would expand for buyers with money.
    • Who bears the cost and who benefits becomes an ethical and distributive question: those with money (wealthier individuals) would be able to purchase organs; sellers would be those with organs or those willing to sell, raising profound ethical concerns.
  • Important implication: price signals influence the allocation of scarce resources, but in markets for essential goods or ethically charged goods, pure price signals may conflict with moral values and policy goals.

Economics as theory and law; the scientific method in economics

  • In economics, observations over time lead to theories about cause and effect (X causes Y).
  • If a relationship holds consistently over a long period, it is often treated as a law rather than a theory.
  • Focus in this course: empirical laws (e.g., the law of diminishing marginal utility, the budget constraint, trade-offs) rather than only theories.
  • Scientific method in economics (simplified):
    • Observe a pattern or relation.
    • Propose a cause-and-effect hypothesis: X causes Y.
    • Test across data or experiments; if robust, treat as an economic law.
  • The importance of two-variable analysis: most discussions and graphs in introductory economics focus on the relationship between two variables (X causes Y) to illustrate core ideas clearly.

Slopes, lines, and reading graphs: basic relationships you should know

  • Key slope concepts for simple graphs:
    • Horizontal line: slope = 0; price is unchanged or quantity is responsive without a price change in the axis context.
    • Vertical line (undefined slope): quantity is fixed with respect to price; price changes do not affect quantity (extreme case of inelastic response).
    • Positive slope: as one variable increases, the other increases (e.g., some supply or demand relationships).
    • Negative slope: as price increases, quantity demanded decreases (classic downward-sloping demand).
  • These slope types appear in basic supply/demand and budget-constraint graphs and are useful for quick intuition about responsiveness.

Real-world links: dating markets, labor, and markets for goods

  • People act as products in supply/demand terms when presenting themselves in dating apps or markets:
    • You “supply” yourself (profile, appearance, skills) and you are in effect offering value to potential partners (consumers).
    • Expected attributes include attractiveness, money, shared interests, and compatibility.
    • The market outcome depends on demand (what others seek) and supply (what you offer).
  • This framing illustrates that many everyday decisions can be analyzed as market-like exchanges, even when ethical boundaries and norms differ from traditional markets.

Inferior vs. superior goods and potential exceptions

  • Most goods follow the typical diminishing marginal utility pattern: MU declines with each additional unit.
  • There are cases of superior or inferior goods that change the MU pattern (e.g., some goods may increase MU for a while due to preference shifts or budget constraints).
  • In many cases, total utility continues to rise with consumption, but the marginal utility gain falls over time.

Ethical and practical implications

  • Economics provides the framework to analyze incentives, trade-offs, and welfare, but ethical considerations consider equity, rights, and values beyond pure efficiency.
  • The organ market thought experiment highlights tensions between efficiency (lower prices, higher supply) and morality, consent, and equity.
  • The instructor emphasizes that teaching may involve provocative examples to reinforce memory and critical thinking, while remaining mindful of ethics and sensitivity.

Key equations and concepts to remember

  • Budget constraint (two goods scenario):
    • Price of A: p<em>A=20p<em>A = 20, Price of B: p</em>B=10p</em>B = 10, Income: I=120I = 120
    • Constraint: pA A + pB B = I \ \
      20A + 10B = 120
  • Solve for B as a function of A:
    • B = rac{I - pA A}{pB} = rac{120 - 20A}{10} = 12 - 2A
  • Feasible region: all pairs $(A,B)$ with 20A+10B2˘26412020A + 10B \u2264 120; unattainable region: 20A + 10B > 120
  • Utility framework:
    • Total Utility: TU=f(Q)TU = f(Q) (for a given good or bundle)
    • Marginal Utility: $$MU = rac{d(TU)}{dQ} \