Macroeconomic Measurement and Indicators
Core concepts
GDP is the market value of all final goods and services produced within a country in a period. Avoid double counting (count final goods, or sum value added). GDP excludes intermediate goods, transfer payments, and non-market activity. Nominal GDP uses current prices; real GDP uses base-year prices to remove inflation. GDP deflator = (nominal ÷ real) × 100.
Measuring growth: growth rate = (new − old) ÷ old × 100. Unemployment: labor force = employed + unemployed; unemployment rate = unemployed ÷ labor force × 100. Types: frictional, structural, cyclical, seasonal. Inflation is measured by CPI or the GDP deflator; real interest rate ≈ nominal − inflation (Fisher approximation).
Business cycle: expansion, peak, contraction, trough. Aggregate demand (C + I + G + NX) and aggregate supply determine output and price level.
Common traps
- Counting intermediate goods or used-goods sales in GDP.
- Mixing nominal and real values when comparing across years.
- Including discouraged workers in the labor force (they are not counted).
- Confusing the CPI (fixed basket) with the GDP deflator (all domestic output).
Worked example
Nominal GDP is $1,200 billion and real GDP is $1,000 billion. Deflator = (1,200 ÷ 1,000) × 100 = 120, meaning prices rose 20% versus the base year. If nominal GDP grows 5% and prices rise 2%, real growth ≈ 3%.
Rule of thumb
Real = nominal adjusted for inflation. Growth ≈ nominal growth − inflation. Unemployment rate uses only those actively seeking work.