Deflation
Deflation occurred periodically in the U.S. during the 19th century (the most important exception was during the Civil War). This deflation was at times caused by technological progress that created significant economic growth, but at other times it was triggered by financial crises — notably the Panic of 1837 which caused deflation through 1844, and the Panic of 1873 which triggered the Long Depression that lasted until 1879. These deflationary periods preceded the establishment of the U.S. Federal Reserve System and its active management of monetary matters. Episodes of deflation have been rare and brief since the Federal Reserve was created (a notable exception being the Great Depression) while U.S. economic progress has been unprecedented.
History of the United States (1918–1945)
The economy eventually recovered from the low point of the winter of 1932–33, with sustained improvement until 1937, when the Recession of 1937 brought back 1934 levels of unemployment. There is a broad consensus among scholars that the New Deal policies did not lengthen and deepen the depression; only 5% of professional historians and 27% of professional economists believe it served to lengthen and deepen the Great Depression. Apart from the WPA and CCC, most New Deal spending programs, such as the PWA and AAA, operated through private firms.