Unemployment in the United States discusses the causes and measures of U.S. unemployment and strategies for reducing it. Job creation and unemployment are affected by factors such as economic conditions, global competition, education, automation, and demographics. These factors can affect the number of workers, the duration of unemployment, and wage levels. Unemployment generally falls during periods of economic prosperity and rises during recessions, creating significant pressure on public finances as tax revenue falls and social safety net costs increase. Government spending and taxation decisions (fiscal policy) and U.S. Federal Reserve interest rate adjustments (monetary policy) are important tools for managing the unemployment rate. There may be an economic trade-off between unemployment and inflation, as policies designed to reduce unemployment can create inflationary pressure, and vice versa. The U.S. Federal Reserve (the Fed) has a dual mandate to achieve full employment while maintaining a low rate of inflation. The major political parties debate appropriate solutions for improving the job creation rate, with liberals arguing for more government spending and conservatives arguing for lower taxes and less regulation. Polls indicate that Americans believe job creation is the most important government priority, with not sending jobs overseas the primary solution. Unemployment can be measured in several ways. A person is defined as unemployed in the United States if they are jobless, but have looked for work in the last four weeks and are available for work. People who are neither employed nor defined as unemployed are not included in the labor force calculation. For example, as of September 2017, the unemployment rate (formally defined as the "U-3" rate) in the United States was 4.2% representing 6.8 million unemployed people. The unemployment rate was calculated by dividing the number of unemployed by the number in the civilian labor force (age 16+, non-military and not incarcerated) of approximately 159.