Which statement correctly distinguishes nominal GDP from real GDP and explains why inflation adjustment is necessary?

• A. Nominal GDP uses current prices; Real GDP uses constant prices; inflation adjustment is necessary to compare across years.
• B. Nominal GDP uses constant prices; Real GDP uses current prices; inflation adjustment is unnecessary.
• C. Nominal GDP excludes government spending; Real GDP includes government spending; inflation adjustment is optional.
• D. Nominal GDP uses current prices; Real GDP uses constant prices; inflation adjustment does not affect year-to-year comparisons.

Answer: (A)

The main idea is that nominal GDP measures the value of production using current-year prices, while real GDP uses constant prices from a base year, removing price changes from the measurement. Inflation adjustment is necessary to compare across years because prices rise over time, so nominal GDP can increase just due to higher prices even if the actual quantity of goods and services produced stays the same. By using constant prices, real GDP shows how much output has genuinely grown, isolating changes in production from changes in the price level. In practice, real GDP is obtained by adjusting nominal GDP with a price index (like the GDP deflator), so year-to-year comparisons reflect real growth rather than inflation.