That’s not a settled answer. Traditionally, there’s a lot of weight put on the New Deal programs of FDR. Others have pointed out that it wasn’t until the start of World War II that the unemployment rate fell below 10 percent. More recent research on the New Deal points out that a lot of the New Deal programs actually hindered the recovery of the economy. So, the effect of the New Deal continues to be debated.
There’s been research that shows the rapid growth of the money supply from 1934 on was particularly beneficial. We stopped having bank failures, and the money supply started ramping up. So I think the growth of the money supply had a role, but some of the things that FDR did—particularly those things that helped stabilize the banking system, like deposit insurance and changes to the gold standard, contributed to the recovery. Of course, FDR’s leadership is hard to quantify, but it helped restore confidence.