<Li> "The length and depth of a country's economic downturn and the timing and vigor of its recovery is related to how long it remained on the gold standard . Countries abandoning the gold standard relatively early experienced relatively mild recessions and early recoveries . In contrast, countries remaining on the gold standard experienced prolonged slumps ." </Li> <P> In a 1995 survey of American economic historians, two - thirds agreed that the Smoot - Hawley tariff act at least worsened the Great Depression . However, many economists believe that the Smoot - Hawley tariff act was not a major contributor to the great depression . Economist Paul Krugman holds that, "Where protectionism really mattered was in preventing a recovery in trade when production recovered". He cites a report by Barry Eichengreen and Douglas Irwin: Figure 1 in that report shows trade and production dropping together from 1929 to 1932, but production increasing faster than trade from 1932 to 1937 . The authors argue that adherence to the gold standard forced many countries to resort to tariffs, when instead they should have devalued their currencies . Peter Temin argues that contrary the popular argument, the contractionary effect of the tariff was small . He notes that exports were 7 percent of GNP in 1929, they fell by 1.5 percent of 1929 GNP in the next two years and the fall was offset by the increase in domestic demand from tariff . </P> <Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (June 2015) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (June 2015) (Learn how and when to remove this template message) </Td> </Tr>

What were the principal causes of the great depression