This document discusses different types of unemployment. It defines long-run unemployment as the natural rate of unemployment, which is the amount of unemployment an economy normally experiences in the long run. Short-run unemployment is cyclical unemployment associated with the business cycle. The document also describes how the government measures unemployment through surveys and defines categories like employed, unemployed, and not in the labor force. It discusses challenges in interpreting unemployment data and explores types of unemployment like frictional unemployment from job searching and structural unemployment from mismatches between available jobs and worker skills.