World War I had a net positive impact on the United States economy, including the agricultural and manufacturing sectors. Over a four-year period— beginning with the onset of the war in Europe, continuing to the U.S. entry into the war, and concluding with the cessation of hostilities in 1919—American exports to Europe almost tripled while domestic investment from the federal government increased from $477 million to more than $8 billion.
This growth in industry was accompanied by a corresponding increase in wages and decrease in unemployment. Meanwhile, the agricultural sector increased its output, helped in part by aggressive government programs.
Much of the economic growth in the United States was generated as a result of the decimation Europe suffered and its need to increase imports, as well as a robust program of armaments undertaken by the U.S. government.