Chapter 1: The Four Core Principles of Economics
What is the cost-benefit principle?
Make decisions if the benefits outweigh the costs. It requires evaluating the full set of costs
and benefits of a choice.
What is willingness to pay?
It’s the maximum amount you are willing to spend for a benefit or to avoid a cost. It helps
translate non-financial benefits into dollar terms.
What is economic surplus?
It’s the total benefits minus total costs from a decision. Good decisions maximize your
economic surplus.
Why can framing effects be misleading?
They influence decisions by manipulating how choices are presented. This can distort proper
cost-benefit analysis.
What is opportunity cost?
It’s the value of the next best alternative you give up when making a choice. Every decision
involves a trade-off.
How does scarcity relate to opportunity cost?
Scarcity forces us to make trade-offs because resources are limited. This leads to opportunity
costs in every decision.
What is a sunk cost?
A sunk cost is a cost that has already been incurred and cannot be recovered. It should not
affect future decisions.
Why should sunk costs be ignored in decision-making?
They are unavoidable regardless of the decision you make. Only future costs and benefits
should be considered.
What is the marginal principle?
Make quantity decisions one unit at a time. Compare marginal benefits to marginal costs for
each additional unit.
What is marginal benefit?
It is the extra benefit from consuming or producing one more unit. It helps determine if
additional units are worthwhile.
What is marginal cost?
It’s the additional cost of producing or consuming one more unit. Compare it to marginal
benefit when making decisions.
What is the rational rule?
Keep doing something until marginal benefit equals marginal cost. This rule helps maximize
economic surplus.
Why do we break quantity decisions into marginal ones?
It simplifies complex decisions. Marginal analysis allows for smarter, incremental choices.
What does the interdependence principle mean?
Your decisions affect and are affected by other choices and people. This includes decisions in
other markets and over time.
How do your own choices affect each other?
Limited resources mean one choice affects what else you can do. Time spent studying
economics is time not spent studying psychology.
How do others’ choices influence yours?
Others' actions can limit or expand your options. For example, if a company hires top
engineers, fewer are left for competitors.
How do different markets affect each other?
A change in one market can influence behavior in another. Lower interest rates in the credit
market can increase housing demand.
How do expectations shape decisions?
Future expectations change what we do today. Anticipating higher prices later may lead you
to buy now.
Why is money used in cost-benefit analysis?
It provides a common measure for comparing all costs and benefits. This includes both
financial and non-financial aspects.
Why is economics considered a way of thinking?
It provides tools to understand decisions and trade-offs. It’s more than money—it’s about
choices in all areas of life.
Chapter 2: Demand and Consumer Choice
What is an individual demand curve?
It shows the quantity a person plans to buy at each price. It reflects personal buying plans
under current conditions.
What is the law of demand?
As price decreases, quantity demanded increases. Demand curves slope downward.
Why do we assume “ceteris paribus” in demand?
It means “all else equal.” We isolate the effect of price on quantity demanded.
What is marginal benefit in terms of demand?
It’s the benefit of one more unit, equal to the price you are willing to pay. The demand curve
is also the marginal benefit curve.
What is diminishing marginal benefit?
Each additional unit gives less satisfaction than the one before. This causes demand curves to
slope down.
What is the rational rule for buyers?
Buy more if the marginal benefit is greater than or equal to the price. Stop when price equals
marginal benefit.
What is market demand?
It is the total quantity demanded by all buyers at each price. It adds up individual demand
curves.
What are the four steps to estimating market demand?
Survey buyers, sum quantities at each price, scale to market size, and plot the demand curve.
This visualizes total market buying behavior.
What causes movement along the demand curve?
A change in the good’s own price. Quantity demanded changes but demand itself does not.
What causes a shift in the demand curve?
Changes in other factors like income or preferences. These alter demand at all prices.
How does income affect demand?
Higher income increases demand for normal goods and decreases demand for inferior goods.
Income shifts the demand curve.
How do preferences shift demand?
Lifestyle changes, trends, or seasons can change what people want. This changes demand at
every price.
What are complements in consumption?
Goods used together, like hot dogs and buns. A rise in one’s price decreases demand for the
other.
What are substitutes in consumption?
Goods used instead of each other. A price rise in one increases demand for its substitute.
How do expectations affect demand?
Anticipating future price changes shifts current demand. Expecting a shortage may increase
current purchases.
What is a network effect?
A good becomes more useful as more people use it. Social media platforms are a common
example.
What is a congestion effect?
A good becomes less useful when more people use it. Traffic jams are a typical case.
What’s the difference between a shift and movement along a demand curve?
Movement is due to price changes; shift is due to other factors. Only shifts change demand
itself.
How do market trends affect individual decisions?
Individual demand depends on market context and peer behavior. Interdependence links
choices across people.
Why do businesses use discounts like “buy one, get one”?
Because marginal benefit falls with each additional unit. Discounts encourage consumers to
buy more by lowering margi
n
Chapter 3: Supply and Producer Choice
What is an individual supply curve?
It shows how much a seller plans to sell at each price. It reflects a business's selling plans.
What is the law of supply?
As price rises, quantity supplied rises. Supply curves slope upward.
Why are sellers considered price-takers in perfect competition?
They sell identical goods in a market with many competitors. Therefore, they must accept the
market price.
What is the marginal benefit to a seller?
It’s the price received for selling an extra unit. In a competitive market, marginal benefit
equals market price.
What is marginal cost in supply?
It’s the cost of producing one more unit. Sellers compare this to the price to decide how
much to produce.
What is the rational rule for sellers?
Keep producing until price equals marginal cost. This maximizes profit.
Why do marginal costs rise?
Because of diminishing marginal product. As more inputs are used, each additional unit adds
less output.
How do fixed and variable costs differ?
Variable costs change with output; fixed costs do not. Marginal cost is based only on variable
costs.
What is the market supply curve?
It shows total quantity supplied by all sellers at each price. It’s built from adding individual
supply curves.
What happens when price changes in the supply curve?
You move along the same supply curve. This changes quantity supplied but not supply itself.
What causes the supply curve to shift?
Changes in factors other than price, like input costs or technology. These alter supply at all
prices.
How do input prices affect supply?
Higher input costs raise marginal cost and reduce supply. Supply shifts left.
How does productivity or technology affect supply?
Improved productivity lowers marginal cost. This increases supply and shifts the curve right.
What are complements in production?
Goods made together, like beef and leather. If the price of one rises, supply of the other also
rises.
What are substitutes in production?
Goods competing for the same resources. A price increase in one reduces supply of the other.
How do expectations shift supply?
If sellers expect higher future prices, they may withhold supply now. This reduces current
supply.
How does the number of sellers affect supply?
More sellers increase supply; fewer sellers decrease it. This shifts the entire supply curve.
Why is the supply curve upward-sloping?
Because higher prices make production more profitable. Also, marginal costs typically rise
with output.
How does the interdependence principle apply to supply?
A firm’s decisions depend on related markets and expectations. Supply choices are never
made in isolation.
What’s the difference between a shift and movement along the supply curve?
Price changes cause movement along the curve. Other factors shift the entire curve.
Chapter 4: Supply, Demand, and Market Equilibrium
What is market equilibrium?
It's the point where the quantity demanded equals the quantity supplied. This determines the
market price and quantity exchanged.
What happens when the market is not in equilibrium?
A surplus or shortage occurs. Prices adjust to move the market back toward equilibrium.
What causes a surplus?
When quantity supplied exceeds quantity demanded. It usually happens when the price is set
too high.
What causes a shortage?
When quantity demanded exceeds quantity supplied. It typically occurs when the price is too
low.
How does price adjust to eliminate a surplus?
Sellers lower prices to increase quantity demanded and reduce quantity supplied. This
restores equilibrium.
How does price adjust to eliminate a shortage?
Buyers compete for limited goods, driving prices up. This reduces quantity demanded and
increases quantity supplied.
What is the role of prices in markets?
Prices act as signals to buyers and sellers. They coordinate economic activity and allocate
resources efficiently.
What is a price ceiling?
It’s a legal maximum price. If set below equilibrium, it creates a shortage.
What is a price floor?
It’s a legal minimum price. If set above equilibrium, it creates a surplus.
How do price ceilings affect markets?
They prevent prices from rising to equilibrium, causing shortages. This may lead to black
markets or rationing.
How do price floors affect markets?
They stop prices from falling to equilibrium, leading to unsold goods. This can result in
waste or government intervention.
What is consumer surplus?
It’s the difference between what buyers are willing to pay and what they actually pay. It
measures buyers’ gains.
What is producer surplus?
It’s the difference between the price sellers receive and their cost of production. It represents
sellers' gains.
What is total surplus?
It’s the sum of consumer and producer surplus. It measures total benefits to society from
market transactions.
When is total surplus maximized?
At market equilibrium. Any deviation leads to inefficiency.
What is deadweight loss?
It’s the loss in total surplus from market inefficiency. Often caused by price controls, taxes,
or subsidies.
How does a shift in demand affect equilibrium?
An increase in demand raises both price and quantity. A decrease lowers both.
How does a shift in supply affect equilibrium?
An increase in supply lowers price and raises quantity. A decrease raises price and lowers
quantity.
What is the effect of simultaneous shifts in supply and demand?
The impact on price and quantity depends on the direction and magnitude of each shift.
Outcomes vary.
Why are markets usually efficient at equilibrium?
Because all mutually beneficial trades occur. No resources are wasted and total surplus is
maximized
Chapter 5: Elasticity
What is price elasticity of demand?
It measures how much quantity demanded responds to a change in price. It shows demand
sensitivity.
What is elastic demand?
When quantity demanded responds strongly to price changes. Elasticity is greater than 1.
What is inelastic demand?
When quantity demanded responds weakly to price changes. Elasticity is less than 1.
What is unit elastic demand?
When the percentage change in quantity equals the percentage change in price. Elasticity
equals 1.
What factors affect price elasticity of demand?
Availability of substitutes, time horizon, necessity vs. luxury, and share of budget. More
substitutes and time make demand more elastic.
What is total revenue?
Price multiplied by quantity sold. It shows how much money a firm brings in.
How does elasticity affect total revenue?
If demand is elastic, a price increase lowers total revenue. If inelastic, a price increase raises
total revenue.
What is cross-price elasticity?
Measures how demand for one good responds to a change in the price of another. Positive for
substitutes, negative for complements.
What is income elasticity of demand?
It measures how quantity demanded changes with income. Positive for normal goods,
negative for inferior goods.
What is price elasticity of supply?
It shows how much quantity supplied responds to price changes. It reflects how easily
producers can change output.
When is supply elastic or inelastic?
Elastic supply means quantity supplied responds a lot; inelastic means it responds little.
Long-term supply is often more elastic.
How do you calculate elasticity?
Elasticity = (% change in quantity) ÷ (% change in price). Use midpoint method for more
accurate results.
Why is elasticity important for firms?
It helps predict how revenue will change with price changes. It's vital for pricing strategy.
How does elasticity affect tax incidence?
The side of the market that is less elastic bears more of the tax burden. Elasticity determines
tax fairness and efficiency.
What is perfectly inelastic demand?
Quantity demanded doesn’t change at all when price changes. The demand curve is vertical.
What is perfectly elastic demand?
Consumers buy any amount at a single price, but none at any other. The demand curve is
horizontal.
What is perfectly inelastic supply?
Quantity supplied is fixed, regardless of price. The supply curve is vertical.
What is perfectly elastic supply?
Sellers will supply any quantity at one price, but none at any other. The supply curve is
horizontal.
Why is elasticity time-dependent?
Consumers and producers adjust more in the long run. Elasticities usually increase over time.
What is the relationship between slope and elasticity?
A steep curve may be inelastic; a flat one is more elastic. But elasticity depends on
percentage changes, not just slope.
Chapter 7: Market Failure and Government Intervention
What is market failure?
When the market fails to allocate resources efficiently. It results in lost surplus or welfare.
What are externalities?
Side effects of economic activity that affect others not involved in the transaction. They can
be positive or negative.
What is a negative externality?
A cost imposed on a third party, like pollution. The market produces too much of the good.
What is a positive externality?
A benefit to third parties, like vaccines. The market produces too little of the good.
How can governments correct externalities?
By using taxes, subsidies, or regulations. The goal is to align private and social costs or
benefits.
What is a Pigouvian tax?
A tax on a good with negative externalities. It reduces overproduction and internalizes the
external cost.
What is a subsidy for positive externalities?
A payment to encourage more production or consumption of a beneficial good. It internalizes
the external benefit.
What is the Coase Theorem?
If property rights are well-defined and transaction costs are low, parties can negotiate to fix
externalities. Government intervention isn’t always needed.
What is a public good?
A good that is non-rival and non-excludable, like national defense. Markets underprovide
these goods.
What is the free-rider problem?
When people benefit from a good without paying for it. This leads to underproduction.
What is a common resource?
A good that is rival but non-excludable, like fish in the ocean. These are overused due to the
tragedy of the commons.
What is the tragedy of the commons?
When individuals overuse and deplete a common resource. It results in inefficiency and
resource exhaustion.
How do governments manage public goods?
They often provide them directly and fund them with taxes. This avoids underprovision.
How do governments manage common resources?
Through regulations, quotas, or property rights. This reduces overuse.
What are merit goods?
Goods the government believes people should consume more of, like education. These often
have positive externalities.
What are demerit goods?
Goods believed to be harmful, like cigarettes. These often have negative externalities and
may be taxed or regulated.
What is information asymmetry?
When one party in a transaction has more information than the other. It can lead to adverse
selection or moral hazard.
What is adverse selection?
When only high-risk participants engage in a market due to asymmetric info. Insurance
markets often suffer from this.
What is moral hazard?
When people take more risks because they don't bear the full consequences. Insurance can
encourage this behavior.
Why does government intervention sometimes fail?
Poor information, unintended consequences, and regulatory capture can cause government
failure. Interventions must be carefully designed.