What the recession of 1919 to 1921 was caused by?

In general terms, it can be attributed to the switch from a wartime to a peacetime economy which followed the end of the First World War. Some countries were more affected than others. Germany, for example, also suffered from an economic infrastructure which had been destroyed by the war yet still had to pay massive compensation to the allied powers. A secondary cause was the Spanish Flu epidemic of 1918-1919 which killed an estimated 50-100 million people. This represented a loss of production capacity (ie workers) as well as purchasing power (ie consumers).