Public opinion: A powerful predictor of U.S. defense spending? A comment

A recent paper in Defence Economics suggests that “a single variable, the public opinion balance,. when accompanied by a control variable measuring the proportion of responses in the ‘residuum’ (no opinion or keep the status quo), permits an accurate prediction of subsequent changes in the rate of change of U.S. defense outlays from the mid-1960s through the 1980s” (Higgs and Kilduff, 1993, p. 227). In contrast, this comment provides evidence that since 1986 the Higgs-Kilduff model frequently mispredicts the direction of U.S. defense spending. In addition, the average prediction error, and its variance, since 1986 consistently exceeds the average prediction error, and its variance, for the years prior to 1986.