Macroeconomics is a sub-section of economics which focuses on the behavior of an entire economy, and the actors that exist at that level, such as the Federal Reserve. Looking through this lens, economists observe the financial decisions that manipulate an economy’s elements, such as interest rates, inflation, deflation, and stagflation. Macroeconomics can also explain phenomena that happen on a country-wide scale, such as different types of unemployment, and aggregate supply or demand. It can also be used to describe the current state of an economy, such as a country’s GDP. Economists use macroeconomics to discuss both historical trends and predictions for a certain economy.