Microeconomics Core, Markets, Elasticity, and Firms
Microeconomics studies individuals, firms, and markets. Master these concepts and you can analyze any market scenario on an exam.
Foundation Concepts
Every market problem starts with scarcity and opportunity cost. Scarcity forces choices. Opportunity cost is the value of the next best alternative you give up. The production possibilities frontier (PPF) shows what you can produce given limited resources.
Comparative advantage drives trade. It means lower opportunity cost in producing a good. Specialization based on comparative advantage makes everyone wealthier.
Supply, Demand, and Equilibrium
The law of demand says quantity demanded falls as price rises. The law of supply says quantity supplied rises as price rises. Market equilibrium occurs where supply meets demand.
Price elasticity of demand measures how responsive quantity is to price changes. Elastic means quantity changes a lot. Inelastic means quantity barely moves. Income elasticity shows whether a good is normal (positive) or inferior (negative).
Surplus, Loss, and Efficiency
Consumer surplus is the difference between what buyers willing pay and actual price. Producer surplus is the difference between actual price and minimum acceptable price.
Deadweight loss occurs when markets are inefficient. Taxes, price controls, and monopolies all create deadweight loss. This is lost total surplus that benefits nobody.
Market Structures
- Perfect competition: Many firms, identical products, free entry, zero economic profit long-term
- Monopoly: Single seller, barriers to entry, produces where marginal revenue equals marginal cost
- Monopolistic competition: Many firms with different products, short-run profits fade as entry increases
- Oligopoly: Few firms with interdependent decisions, analyzed using game theory
| Term | Meaning |
|---|---|
| Scarcity | The central economic problem: unlimited wants but limited resources. Forces choices and tradeoffs. |
| Opportunity cost | The value of the next best alternative foregone when making a choice. The true cost of any decision. |
| Production possibilities frontier (PPF) | Graph showing maximum combinations of two goods producible given resources. Points on the curve are efficient; inside are inefficient; outside are unattainable. |
| Comparative advantage | Lower opportunity cost in producing a good. Basis for specialization and trade. |
| Law of demand | Quantity demanded falls as price rises, holding other factors constant. Downward-sloping demand curve. |
| Law of supply | Quantity supplied rises as price rises, holding other factors constant. Upward-sloping supply curve. |
| Market equilibrium | Price and quantity where supply equals demand. Shortages below equilibrium; surpluses above. |
| Price elasticity of demand | % change in quantity demanded / % change in price. Elastic (|E|>1) means quantity is responsive; inelastic (|E|<1) means unresponsive. |
| Income elasticity | % change in quantity / % change in income. Positive for normal goods, negative for inferior goods. |
| Consumer surplus | Difference between what consumers are willing to pay and what they actually pay. Area below demand curve, above price. |
| Producer surplus | Difference between the price producers receive and their minimum acceptable price. Area above supply curve, below price. |
| Deadweight loss | Loss of total surplus due to market inefficiency (taxes, price controls, monopoly). |
| Perfect competition | Many firms, identical products, free entry/exit, price takers. Long-run: P = MC = ATC, zero economic profit. |
| Monopoly | Single seller, no close substitutes, barriers to entry. Produces where MR = MC; charges price from demand curve. Deadweight loss vs competitive outcome. |
| Monopolistic competition | Many firms with differentiated products. Short-run profits, but entry drives long-run profit to zero. Excess capacity. |
| Oligopoly | Few firms with interdependent decisions. Analyzed with game theory (e.g., prisoner's dilemma, Nash equilibrium). |
Macroeconomics Core, GDP, Inflation, and Growth
Macroeconomics studies the entire economy. You need to know the key measures, the AS-AD model, and how policy works.
Measuring the Economy
Gross Domestic Product (GDP) is the market value of all final goods and services produced in a year. The formula is GDP equals consumption plus investment plus government spending plus exports minus imports.
Nominal GDP uses current prices. Real GDP adjusts for inflation. Real GDP measures actual output growth. The GDP deflator converts nominal to real GDP.
Inflation is a general rise in price levels. It erodes purchasing power. The Consumer Price Index (CPI) measures inflation by tracking a fixed basket of goods.
The unemployment rate counts only people actively seeking work. Frictional unemployment occurs between jobs. Structural unemployment happens when skills don't match available jobs. Cyclical unemployment results from recessions. The natural rate equals frictional plus structural unemployment.
The AS-AD Model
Aggregate demand (AD) is total demand for goods at each price level. It slopes downward due to wealth effects, interest rate effects, and exchange rate effects.
Aggregate supply (AS) is total output supplied at each price level. Short-run aggregate supply (SRAS) slopes upward. Long-run aggregate supply (LRAS) is vertical at full employment.
AS-AD equilibrium happens where the curves intersect. Short-run equilibrium determines price and output. Long-run equilibrium occurs at potential GDP.
Policy Tools
Fiscal policy uses government spending and taxation. Expansionary fiscal policy increases spending or cuts taxes. Contractionary fiscal policy reduces spending or raises taxes.
Monetary policy uses money supply and interest rates. The Federal Reserve uses three main tools: open market operations, the discount rate, and reserve requirements. Money supply includes M1 (currency plus checkable deposits) and M2 (M1 plus savings accounts).
The Phillips curve shows an inverse relationship between inflation and unemployment in the short run. The long-run Phillips curve is vertical at the natural unemployment rate.
| Term | Meaning |
|---|---|
| Gross Domestic Product (GDP) | Market value of all final goods and services produced within a country in a year. GDP = C + I + G + (X - M). |
| Real vs nominal GDP | Nominal GDP uses current prices; real GDP is adjusted for inflation using a base year. Real GDP measures actual output growth. |
| GDP deflator | Nominal GDP / real GDP × 100. A measure of economy-wide price level. |
| Inflation | General rise in the price level. Measured by CPI or GDP deflator. Erodes purchasing power. |
| Consumer Price Index (CPI) | Measures changes in the price of a fixed basket of consumer goods and services. |
| Unemployment rate | Unemployed / labor force × 100. Only counts those actively seeking work. |
| Types of unemployment | Frictional (between jobs), structural (skills mismatch), cyclical (due to recession). Natural rate = frictional + structural. |
| Aggregate demand (AD) | Total demand for goods and services at each price level. Downward sloping because of wealth, interest rate, and exchange rate effects. |
| Aggregate supply (AS) | Total output supplied at each price level. SRAS upward sloping; LRAS vertical at full employment. |
| AS-AD equilibrium | Intersection of AD and SRAS determines short-run price level and real output. LRAS determines long-run equilibrium at potential GDP. |
| Business cycle | Short-run fluctuations in real GDP around potential output. Phases: expansion, peak, contraction, trough. |
| Fiscal policy | Government spending and taxation to influence the economy. Expansionary (increase G or cut T); contractionary (opposite). |
| Monetary policy | Central bank actions affecting money supply and interest rates. Expansionary lowers rates; contractionary raises them. |
| Federal Reserve tools | Open market operations, discount rate, reserve requirements, interest on reserves. OMO is the primary tool. |
| Money supply (M1, M2) | M1: currency plus checkable deposits. M2: M1 plus savings, small time deposits, money market funds. |
| Phillips curve | Short-run inverse relationship between inflation and unemployment. Long-run Phillips curve is vertical at the natural rate. |
Policy, International, and Applied Economics
These concepts complete any introductory course. They appear heavily on AP exams and in applied business classes.
Economic Effects and Mechanisms
The multiplier effect means a change in spending produces a larger change in GDP. The spending multiplier equals 1 divided by (1 minus the marginal propensity to consume). Crowding out happens when government borrowing raises interest rates, reducing private investment.
The quantity theory of money states that money supply times velocity equals price level times real output. This classical view treats inflation as always monetary in origin.
International Trade and Finance
The balance of payments records all international transactions. The current account covers trade and income. The capital account covers investment flows.
Exchange rates are the price of one currency in terms of another. Floating rates respond to markets. Fixed rates are pegged by central banks.
Tariffs are taxes on imports. Quotas are quantity limits on imports. Both raise domestic prices and create deadweight loss. Comparative advantage drives trade gains, not absolute advantage.
Market Failures and Government Intervention
An externality is a cost or benefit imposed on third parties. Negative externalities (pollution) lead to overproduction. Positive externalities (vaccination) lead to underproduction.
Public goods like national defense are non-rivalrous and non-excludable. Markets undersupply them due to the free-rider problem.
A price ceiling sets a legal maximum price. Below equilibrium, it creates shortages. A price floor sets a legal minimum. Above equilibrium, it creates surpluses.
Tax incidence shows how tax burden splits between buyers and sellers based on elasticities. The Laffer curve relates tax rates to tax revenue. Too-high rates can reduce revenue.
Long-term Growth
The Gini coefficient measures income inequality from 0 (perfect equality) to 1 (perfect inequality).
Economic growth is sustained increase in real GDP per capita. It comes from labor, capital, human capital, and technology. The Solow growth model shows that capital accumulation alone produces diminishing returns. Technology drives long-run growth.
| Term | Meaning |
|---|---|
| Multiplier effect | A change in spending produces a larger change in GDP. Spending multiplier = 1/(1-MPC). Tax multiplier = -MPC/(1-MPC). |
| Crowding out | Government borrowing raises interest rates, reducing private investment. Weakens the effectiveness of expansionary fiscal policy. |
| Quantity theory of money | MV = PY. Money supply times velocity equals price level times real output. Classical view: inflation is always a monetary phenomenon. |
| Balance of payments | Record of a country's international transactions. Current account (trade, income) + capital account (investment) must balance. |
| Exchange rates | Price of one currency in terms of another. Floating rates set by markets; fixed rates pegged by central banks. |
| Tariffs and quotas | Trade barriers. Tariffs are taxes on imports; quotas are quantity limits. Both raise domestic prices and cause deadweight loss. |
| Absolute vs comparative advantage | Absolute: produce more with the same resources. Comparative: produce at lower opportunity cost. Trade gains come from comparative advantage. |
| Externality | Cost or benefit imposed on third parties. Negative (pollution) leads to overproduction; positive (vaccination) to underproduction. |
| Public goods | Non-rivalrous and non-excludable (national defense, lighthouses). Free-rider problem leads markets to underprovide. |
| Price ceiling | Legal maximum price (rent control). Below equilibrium creates shortages and deadweight loss. |
| Price floor | Legal minimum price (minimum wage). Above equilibrium creates surpluses (unemployment in labor markets). |
| Tax incidence | How the burden of a tax is shared between buyers and sellers. Depends on relative elasticities. |
| Laffer curve | Relationship between tax rates and tax revenue. Too-high rates can actually reduce revenue. |
| Gini coefficient | Measure of income inequality from 0 (perfect equality) to 1 (perfect inequality). |
| Economic growth | Sustained increase in real GDP per capita. Driven by labor, capital, human capital, and technology (productivity). |
| Solow growth model | Neoclassical model where growth comes from capital accumulation, labor growth, and technology. Diminishing returns to capital alone. |
How to Study economics Effectively
Mastering economics requires the right study approach, not just more hours. Research in cognitive science shows three techniques produce the best outcomes: active recall (testing yourself rather than re-reading), spaced repetition (reviewing at optimized intervals), and interleaving (mixing related topics).
FluentFlash is built around all three. The FSRS algorithm schedules every term for review at exactly the moment you are about to forget it. This maximizes retention while minimizing study time.
Why Active Recall Works
The most common mistake is relying on passive review. Re-reading notes, highlighting passages, or watching videos feels productive but produces only 10-20% of the retention that active recall achieves. Flashcards force your brain to retrieve information, which strengthens memory far more than recognition alone.
Pair active recall with spaced repetition scheduling. You can learn in 20 minutes daily what would take hours of passive review.
Your Practical Study Plan
- Create 15-25 flashcards covering highest-priority concepts
- Review them daily for the first week using FSRS scheduling
- As cards become easier, intervals expand automatically from minutes to days to weeks
- Work on material at the edge of your knowledge
- After 2-3 weeks, economics concepts become automatic rather than effortful
- 1
Generate flashcards using FluentFlash AI or create them manually from your notes
- 2
Study 15-20 new cards per day, plus scheduled reviews
- 3
Use multiple study modes (flip, multiple choice, written) to strengthen recall
- 4
Track your progress and identify weak topics for focused review
- 5
Review consistently, daily practice beats marathon sessions
Why Flashcards Work Better Than Other Study Methods for economics
Flashcards are one of the most research-backed study tools for any subject, including economics. The reason comes down to how memory works. Reading a textbook stores information in short-term memory, but without retrieval practice, it fades within hours. Flashcards force retrieval, which transfers information from short-term to long-term memory.
The Testing Effect
Hundreds of peer-reviewed studies document the testing effect. Students who study with flashcards consistently outperform those who re-read by 30-60% on delayed tests. This is not because flashcards contain more information. It is because retrieval strengthens neural pathways that passive exposure cannot.
Every time you successfully recall an economics concept from a flashcard, you make that concept easier to recall next time.
FSRS Optimization
FluentFlash amplifies this effect with the FSRS algorithm. This modern spaced repetition system schedules reviews at mathematically-optimal intervals based on your performance. Cards you find easy get pushed further ahead. Cards you struggle with come back sooner.
Over time, this builds remarkable retention with minimal time investment. Students using FSRS-based systems typically retain 85-95% of material after 30 days, compared to roughly 20% retention from passive review alone.