Economic Terms – Comprehensive Study Notes
(MIT‑Level, First Principles, Rigorous Reasoning, Edge‑Case Analysis, and a Challenging Problem)
1. Introduction
Economic terms are the language of finance, policy, and research. Mastery of these terms is essential for:
- Policy analysis (monetary, fiscal, trade)
- Financial decision‑making (portfolio, risk management)
- Academic research (econometrics, DSGE, growth theory)
- Informed citizenship (understanding current affairs)
These notes start from first principles, build rigorous derivations, explore edge cases, and culminate in a challenging problem that integrates multiple concepts.
2. Macro‑Economic Foundations
| Term | Definition | Key Formula | First‑Principle Derivation | Edge Cases |
|---|---|---|---|---|
| Gross Domestic Product (GDP) | Total monetary value of all final goods & services produced within a country in a period. | (GDP = C + I + G + (X - M)) | Derived from expenditure identity; each component represents a class of final consumption. | Zero‑growth (GDP = 0) → “shut‑down” economy; negative GDP (rare) → contraction. |
| Gross National Product (GNP) | GDP + Net factor income from abroad. | (GNP = GDP + NFIF) | Adds income earned by residents abroad, subtracts foreign residents' income domestically. | Very high NFIF → “income‑rich” but low domestic production. |
| National Income (NI) | Total wages + profits + rents + taxes – subsidies. | (NI = W + \Pi + R + T - S) | Based on income accounting identity. | Zero NI → all production is transferred as tax/subsidies. |
| Consumer Price Index (CPI) | Weighted average price of a basket of goods & services. | (CPI_t = \frac{\sum_i w_i P_{i,t}}{\sum_i w_i P_{i,0}}) | Derived from Laspeyres index. | CPI > 1 → inflation; CPI < 1 → deflation. |
| Producer Price Index (PPI) | Weighted average of prices received by producers. | Similar to CPI but uses producer weights. | Derived from input‑side basket; reflects cost pressures. | PPI > CPI → indicates cost‑pushing inflation. |
| Inflation | Sustained rise in price level. | (\pi_t = \frac{CPI_t - CPI_{t-1}}{CPI_{t-1}}) | Derived from price index difference. | Hyperinflation: (\pi \gg 1); Stagflation: inflation + unemployment. |
| Unemployment | Labor market slack. | (u = \frac{U}{L}) where (U) = unemployed, (L) = labor force | Derived from labor‑force survey. | Natural Rate: structural + frictional; Cyclical component depends on AD. |
2.1. Real vs. Nominal
- Nominal GDP: measured at current prices.
- Real GDP: adjusted for price changes using a base‑year price index.
[ Real\ GDP_t = \frac{Nominal\ GDP_t}{P_t/P_0} ] - Real GDP per capita: ( \frac{Real\ GDP}{Population}).
3. Monetary Theory
| Term | Definition | Key Equation | Derivation | Edge Cases |
|---|---|---|---|---|
| Money Supply (M) | Aggregate of monetary assets available. | (M_1 = C + D) ( |