I spent the past six months reading about Calvin Coolidge. I was interested in why the 1920s were a period of great prosperity and why the severe recession/ depression of 1920-1921 was so short. At its peak, there was 25% unemployment. Gross domestic product dropped by 6.9% in one report.
The recession of 1920–21 was characterized by extreme deflation — the largest one-year percentage decline in around 140 years of data. The Department of Commerce estimates 18% deflation, Balke and Gordon estimate 13% deflation, and Romer estimates 14.8% deflation. The drop in wholesale prices was even more severe, falling by 36.8%, the most severe drop since the American Revolutionary War. This is worse than any year during the Great Depression (adding all the years of the Great Depression together, however, yields more severe deflation). The deflation of 1920–21 was extreme in absolute terms, and also unusually extreme given the relatively small decline in gross domestic product.
The Harding-Coolidge administration took office in March 1921 and the recession was over in months. Why ? Governments were smaller then and had less influence on the economy. The Wilson Administration has been widely described as the equivalent of a fascist regime with its war time controls and economic meddling. Again from the Wikipedia article: