Incumbent Party’s Expected Vote Margin = 1.14 −.83 × (Years in Office) +4.51 × (4th-Year Income Growth) +1.66 × (3rd-Year Income Growth) −1.04 × (2nd-Year Income Growth) −2.34 × (1st-Year Income Growth)
Most of the ingredients in this recipe for success at the polls are very familiar to students of American presidential elections. The incumbent party tends to do less well the longer it has held the White House. Robust income growth in the year of the election provides a huge boost to the incumbent’s electoral prospects. Income growth in the preceding year matters much less.
The share of income going to the top one-tenth of 1 percent of American families quadrupled between 1970 and 1998, leaving the 13,000 richest families with almost as much income as the 20 million poorest families. Ordinary Americans seem to be well aware of this growing gap between rich and poor. In a recent opinion survey, 74 percent of the respondents acknowledged that the difference in incomes between rich and poor people in the United States is larger today than it was 20 years ago, and 42 percent said it was much larger. Most of these respondents added that the growing gap is a bad thing, though many others acknowledged that they hadn't thought about that.