Clement Juglar in 1860 was among the first to analyze business cycles using statistical data and identified cycles occurring every 8-11 years. Wesley Mitchell further empirically studied business cycles and helped establish the National Bureau of Economic Research. The main instruments to control business cycles are monetary policy by central banks, fiscal policy by governments, and direct controls such as price controls. Monetary policy involves interest rates and money supply, fiscal policy involves government spending and taxation, and direct controls more directly target prices, wages, and allocation of resources. No single measure can fully control cycles, so a combination of these instruments should be used.