Nominal GDP measures the total value of all goods and services produced in a country within a specific time period, usually a year, without adjusting for inflation. It reflects the current market prices, making it useful for comparing economic performance over time in terms of actual monetary value. However, nominal GDP can be misleading when comparing different time periods or countries, as it does not account for changes in price levels. To get a clearer picture of economic growth, economists often use real GDP, which adjusts for inflation and provides a more accurate representation of an economy's size and health.