From the Wall Street Journal:
Mr. Barro is a professor of economics at Harvard and a senior fellow at Stanford University's Hoover Institution. Mr. Redlick is a recent Harvard graduate. This op-ed is based on a working paper issued by the National Bureau of Economic Research in September.
The global recession and financial crisis have refocused attention on government stimulus packages. These packages typically emphasize spending, predicated on the view that the expenditure "multipliers" are greater than one—so that gross domestic product expands by more than government spending itself. Stimulus packages typically also feature tax reductions, designed partly to boost consumer demand (by raising disposable income) and partly to stimulate work effort, production and investment (by lowering rates).
The existing empirical evidence on the response of real gross domestic product to added government spending and tax changes is thin. In ongoing research, we use long-term U.S. macroeconomic data to contribute to the evidence. The results mostly favor tax rate reductions over increases in government spending as a means to increase GDP.
For defense spending, the principal long-run variations reflect the buildups and aftermaths of major wars—World War I, World War II, the Korean War and, to a much lesser extent, the Vietnam War. World War II tends to dominate, with the ratio of added defense spending to GDP reaching 26% in 1942 and 17% in 1943, and then falling to -26% in 1946.
Wartime spending is helpful for estimating spending multipliers for three key reasons. First, the variations in spending are large and include positive and negative values. Second, since the main changes in military spending are independent of economic developments, it is straightforward to isolate the direction of causation between government spending and GDP. Third, unlike many other countries during the world wars, the U.S. suffered only moderate loss of life and did not experience massive destruction of physical capital. In addition, because the unemployment rate in 1940 exceeded 9% but then fell to 1% in 1944, there is some information on how the multiplier depends on the strength of the economy....MORE