Macroeconomics is a branch of economics that studies how an overall economy—the market systems that operate on a large scale—behaves. Macroeconomics studies economy-wide phenomena such as inflation, price levels, rate of economic growth, national income, gross domestic product (GDP), and changes in unemployment. Some of the key questions addressed by macroeconomics include: What causes unemployment? What causes inflation? What creates or stimulates economic growth? Macroeconomics attempts to measure how well an economy is performing, to understand what forces drive it, and to project how performance can improve. Macroeconomics deals with the performance, structure, and behavior of the entire economy, in contrast to microeconomics, which is more focused on the choices made by individual actors in the economy ((like people, households, industries, etc.). There are two sides to the study of economics: macroeconomics and microeconomics. As the term implies, macroeconomics looks at the overall, big-picture scenario of the economy. Put simply, it focuses on the way the economy performs as a whole and then analyzes how different sectors of the economy relate to one another to understand how the aggregate functions.