A KEY judgment shaping every presidential campaign involves voters' answers to the question ``Is it time for a change?'' If a majority believe so, the out-of-power party benefits. If a majority answers ``no,'' the incumbents gain. Most of the conditions needed for voters to make up their minds on this question are by now in place. The state of the economy at election time is now a given, and assessments of the Reagan administration are pretty well fixed. George Bush and Michael Dukakis still have more than seven weeks to change minds - and through events like the presidential debates they may yet achieve a decisive shift in voters' judgments of their ability and other personal characteristics. They are not likely to change thinking much more on the state of the nation.
So what's the verdict? Is it time for a change? Many analysts have thought that, after eight years of Reaganism, the public was ready to try something new. The persistence of a clear majority in opinion polls saying they wanted the next president to change direction in dealing with the nation's problems, rather than follow ``the same policies as the Reagan administration,'' helped form these experts' conclusion.
In fact, this poll finding is highly misleading. Virtually every time a variant of the question has been asked, going back to the presidency of Franklin Roosevelt, a majority has endorsed a shift from the incumbent's policies. That has not meant, however, support for some specific alternative to the incumbent - only that all possible ``something elses'' are preferred to him.
Testing specific alternatives yields a very different picture. In early August of this year, for example, the CBS News/New York Times poll asked whether ``you think the Reagan administration has been too conservative, or not conservative enough?'' Of those with an opinion, 17 percent said it has been too conservative - but 42 percent found it not conservative enough. In the context of a Bush-Dukakis race, the latter simply are not what we normally think of as voters for change.
Views on the economy are bound to influence the electorate's conclusions on whether it's time to change: These views are now quite positive. The University of Michigan's Index of Consumer Sentiment was 97.4 in August - near the high end of modern experience and the highest in more than two years.
By a margin of 69 to 26 percent, respondents to an early August CBS News/New York Times poll said they considered themselves better off than they were eight years earlier. By 40 to 16 percent in an early September Roper organization survey, respondents declared themselves better off than they had been four years previously. Fifty-seven percent in this latter poll expected to be better off four years hence than they are now, just 6 percent worse off. A survey taken Sept. 8-11 by CBS News and the New York Times found 68 percent describing the nation's economy as good, 31 percent as bad. Seventy-four percent said their family's financial position was good, just 15 percent bad.
In a question favored by many analysts, respondents are asked whether they think things in general are moving in the ``right direction'' or are off on the ``wrong track.'' The former response has been increasing over the last two months.
Stanley Greenberg, who polls for many Democrats, noted in early September that ``in every statewide and every congressional poll that we've done in the last two weeks, more people thought the country was moving in the right direction than off on the wrong track, whereas two months ago we barely had a district or state - including ones with low unemployment like Delaware and Connecticut - where the right direction exceeded the wrong track.''
He concluded that the shift ``is part of a general mood in which people are reevaluating where the economy is - beginning to believe that the Reagan years brought positive gains at the economic level that are real....''
We shouldn't rely much on responses to any one question. It's not clear which has come first over the past couple of months: a more favorable assessment of the economy, leading more people toward Mr. Bush; or a political shift toward the Republicans, leading more people to assert that the economy is on track.
Whatever the source of their views, do Americans think it is time for a change? In mid-September, the answer is ``no.'' Unless something happens to alter this judgment, which is unlikely, Mr. Dukakis will have to beat Bush decisively in personal terms - leadership, character, etc. - to prevail Nov. 8.