When turnout fell to a near-historic low in 1988, the two sources of government statistics suggested opposite reasons. One is that fewer and fewer people are registered to vote, and the other that registered voters are going to the polls less and less.
According to the figures supplied by state election officials who tally up county registration totals and record election returns, voting by registered voters is down 15 percentage points since 1960: 85.4% voted that year, but only 70.5% in 1988. By contrast, the U.S. Census reported that 86.2% of registered voters cast ballots in 1988, down only 4.8 percentage points since 1968 (when the Census postelection sample surveys of both registration and voting were first undertaken) (U.S. Bureau of Census, 1989). The 1988 result confirmed the earlier Census summary conclusion for the presidential elections between 1968-80 that registered voters “overwhelmingly go to the polls” (U.S. Bureau of Census, 1984a).
The Census surveys show that falling registration is the more important cause of declining turnout: the level slipped from 74.3% in 1968 to 66.6% in 1988, or 7.7 percentage points. Adjusting that result downward by about 10% to correct for the tendency by some respondents to tell the Census interviewers they are registered when they are not, the 1988 level of registration was 59%. State data, by contrast, show a much higher registration level: 70.9% in 1988, off only 4.5 percentage points since 1960.