Well, the economy didn't really change at this time. Rather, it changed in the early 1930's (1932 - 1933). President Roosevelt changed many things within the economy, improving the Gross National Product (GNP) to 10.2% Up to the 1940's, Roosevelt dropped the total people unemployed under 19%, and raised the total economy by 56%. He also did many other things, but they weren't specified fr this answer.
