This fall on the campaign trail, unlike 1976, President Carter is making few ringing declarations that the nation will enjoy a rosy futurue with rapid economic growth and less inflation if he is elected. Nor is there a drumbeat of promises of major new federal programs, except national health insurance, that would be launched if he gets a second term.

The president has little to say about the economic record of the past 3 1/2 years, except to point out the extraordinary numbers of new jobs that have been created -- 8.5 million, more than in any comparable period in U.S. history. When asked about that record, he usually takes refuge in a "bright" but ill-defined future.

Last week in Youngstown, Ohio, during a mini-version of one of his town meeting appearances that was being televised, Carter got this question: "You mentioned and concocted the misery index in 1976. You put unemployment together with inflation, and you came up with an intolerable figure of 12 percent. Right now in Mahoning Valley our misery index is 24 percent, at least . . . When I talked to business people, they don't know whether to manufacture items for Christmas, whether to hire people for Christmas. They don't seem to have faith in our system and in our economy. What can you do to help us? Please help."

Carter ticked off some recent economic statistics and added, "I think the severe recession that we anticipated, coming from the very high increase in OPEC oil prices, has not been nearly so severe as we thought, and we are well on the road back to recovery. I think we'll have a good Christmas . . . I think the future looks very bright for us."

To the president's great good fortune, in recent weeks it has become clear the economy turned upward again in July or August after the swift plunge of the second quarter. Unemployment, at 7.5 percent, is well below what most economists expected. Inflation in consumber prices, according to the broad personal consumption deflator, was running at an 8.6 percent annual rate in the third quarter, compared with a 12.5 percent rate in the first three months of 1980.

Since changes have produced a shift in public's economic mood that undoubtedly will benefit Carter at the polls. The Conference Board's index of consumer confidence, for example, jumped from a low of 42 in May to 76 in September.

But even if voters go to the polls thinking the worst of this recession is over, they aren't going to be giving Carter any medals for his management of the economy -- certainly not in the Mahoning Valley of Ohio, where steel plant closings have sent unemployment soaring.

Recognizing this, Carter tries at every campaign stop to shift the focus from his own record to his Republican opponent, Ronald Reagan, and his proposals for large, across-the-board personal income-tax cuts, which Carter argues would be "inflationary" and would "pile up federal deficits and erode the value of our money.

"I propose instead that we rely on the same values, the same common sense that built our country in the first place," Carter told an audience at the National Press Club recently. "I propose that we encourage capital investment in new plants and equipment, the investments we need to increase worker productivity." To that end, he has offered a relatively modest $27.6 billion tax cut for next year, with more than half going to business and much of the remainder intended to offset Jan 1 increases in Social Security taxes.

Carter rarely misses an opportunity to point out the inflation risks inherent in his opponent's push for huge personal income-tax cuts. At the same time he is avoiding promises of new federal largesse, the president runs down a long list of existing programs -- urban grants, aid for mass transit, pollution control and energy assistance among them -- which he says Reagan would reduce or eliminate once in office.

The message Carter seeks to convey is one of risk: I am safe; Reagan would be risky. "If we choose the right policies for the future, we can encourage abundance, opportunity and stable prices. If we choose the wrong policies, we can accelerate inflation, jeopardize savings and jobs and discourage investment in the future," he declared at the Press Club in what was intended to be the major economic speech of the campaign.

But Carter, who so often in his term has talked of "sacrifice," is understandably reticent to stress the real sacrifices his own policy would require in the next few years to reach the land of "abundance, opportunity and stable prices" later on. That the president has come to adopt such a policy, one so different from what he advocated in 1976, is a result of the sobering economic events of the past three years.

The key economic question for a voter next month is whether he believes the nation can again achieve swift, noninflationary growth via large personal income-tax cuts (with smaller cuts for business), as Reagan claims, or whether the world is now so inflation-prone that such an approach would blow the lid off, as Carter asserts.

The president's plan involves holding down consumption by individuals to free resources for business investment. More investment should mean faster growth in productivity, which is the key to rising living standards and lower inflation rates, Carter and his advisers believe.

Carter intends to achieve this result by letting personal income taxes rise, courtesy of the impact of inflation on progressive rates, while cutting taxes for businesses that invest in new plants and equipment. If the government collects a dollar in taxes, the individual who paid it can't spend it, whether for hamburger, a car, clothes or a day at the races.

If the government can resist spending it -- a major assumption -- and instead uses it to reduce the size of its budget deficit (or increase the size of a surplus), that dollar has been "saved," albeit involuntarily on the part of the taxpayer. With the dollar in hand, if it still has a deficit, the government needs to borrow less than it otherwise would have. Alternatively, if it already has a surplus, the government can pay off an additional dollar's worth of national debt. Either way, that dollar collected from the taxpayer becomes available to private financial markets to finance private investment.

Despite the $62 billion deficit in fiscal 1980, which ended last month, Carter and his budget and economic advisers argue that in a second term he would indeed resist spending those additional tax dollars. As evidence, the advisers cite the fiscal 1981 budget in which Carter recommended cutting nondefense spending in real terms, that is, after adjusting for inflation.

Carter himself, in his economic speech, declared, "We have made substantial progress in controlling the budget. The rate of real growth in government spending is half what it was when I took office, and the budget deficit is less than half as large a portion of the gross national product."

Reagan, of course, says he would sharply slow the growth in government spending, which would require deep cuts in some programs that he has refused to spell out -- a point hit again and again by Carter.

"Because of the great massive across-the-board tax cut proposed under the Reagan-Kemp-Roth proposal, [Reagan] would need to cut over $130 billion from the federal government to achieve a balanced budget [in 1983]," the president told 1,500 people gathered earlier this month at Hofstra University on Long Island at another of his town-meeting campaign appearances. "If you eliminate . . . defense and entitlement programs, the total remaining federal budget is only $150 billion. . . ."

Carter said, "No president, and no Congress, has ever intentionally chosen to be wrong in shaping economic policies for the United States. But there have been occasions when the effect of their policies was to worsen the already negative trends in our economy." He wasn't making just a subtle dig at Reagan's recommendations.

The president is acutely conscious that in late 1978 and early 1979 -- and perhaps in 1977, too -- his policies overstimulated the economy and added to inflation. OPEC, his advisers acknowledge, was not the entire problem, either in terms of inflation or as the root cause of the 1980 recession.

What Carter now is proposing for 1981 and beyond is a cautious policy of a moderately paced recovery with an attempt to encourage more investment at the expense of some consumption. It is an extension of the administration policy, which early last year began to seek to restrain economic activity, not boost it.

This policy ultimately had as its goal keeping the OPEC-generated surge in inflation last year from becoming fully reflected in American wages, a development that would have pushed inflation to a new, higher plateau. There is preliminary evidence, such as in the unusually moderate increases in the average hourly earnings index over the past three months, that this policy may have worked -- though part of the price was a short recession.

Many times since 1976 Carter has been accused of doing a flip-flop on economic policy. For instance, he proposed and later withdrew the infamouus $50 rebate, and 1978 he had to scale back the size of the tax cut he requested when the economy proved stronger than expected.

But the true shift has been the one toward a far more limited view of what is possible in terms of managing the economy. Reagan, unburdened with either a record as president or direct experience in dealing with the intractability of inflation, is far freer to make sweeping promises, just as Carter himself did the last time around. Carter, with his record and his experience, has been able to afford no such luxury in the 1980 campaign.