President Carter is in the White House today less because of his personal qualities than because he was "widely perceived as an acceptable Democrat" in a time when economic worries strengthened party loyalties, a major study of the 1976 election has concluded.

The first full-scale analysis of 1976 voter interviews by the Center for Political Studies at the University of Michigan was presented to the convention of the American Political Science Association here Friday night by Prof. Arthur H. Miller.

Miller was co-author of the paper with Warren E. Miller, also of the Michigan center, which since 1952 has been the major source of voter studies and analyses for the academic community.

The study tends to confirm - rather than contradict - most popular interpretations of the Carter victory over President Ford. But the strong emphasis on the economic issues and partisan appeals underlying the narrow victory highlight the potential danger to Carter from current complaints by union and black leaders about his administration's inability to reduce unemployment.

In perhaps its key finding, the CPS study said:

"Because of his identification with past Democratic leaders, his selection of [Walter F.] Mondale as a running mate, his positions on specific economic issues and his 'common' background, Carter was widely perceived as an acceptable Democrat . . . Let us not overlook, however, that the course of the general campaign, evaluations of Carter declined. Perhaps as uncertainty about him decreased and more information became available, Carter began to be evaluated more on the basis of his own performance and less as the recipient of projections of the ideal Democratic candidate."

"In the end," is says, "Carter lost 20 percent of his [Democratic] partisan supporters, who voted for Ford because they saw him as more competent and trustworthy and because they agreed with his decisions and were satisfied by his policy performance."

The Democratic defection rate, Arthur Miller noted in an interview, was less than half the 42 per cent defection of Democrats who bolted their party in 1972 to support President Nixon over Sen. George S. McGovern (S.D.).

On the other hand, Ford lost 14 per cent of the Republicans - the highest GOP defection rate since Sen. Barry Goldwalter (R-Ariz.) was challenging President Johnson in 1964. The defectors tended to disagree with Ford's pardon of Nixon and to believe the Democrats would do better on the economic issues, particularly unemployment.

A similar analysis by the same authors of the 1972 election stirred great controversy in academic circles, by arguing that Nixon's victory over McGovern was essentially a demonstration of an increasing "ideological" polarization of the American people, which overwhelmed old party loyalties.

In 1976, they said, Carter's and Ford's votes were almost exactly "what would have been expected . . . on the basis of party identification alone."

But they assert it would be a mistake to believe that issues and personal judgments of candidates' competence were therefore insignificant.

In fact, their polling shows "only a slight diminution" in "ideological thinking" between 1972 and 1976 and no real shift in the liberal-conservative divisions within the Democratic electorate and between Democrats and Republicans.

What did change, the authors say, was the relative importance of differenct issues. The economic issues - principally unemployment and inflation - were rated "most important" by 71 per cent of the people in 1976, compared to 28 per cent in 1972. Foreign policy issues dropped sharply in importance after the Vietnam was ended in 1975.

And the "social issues" that loomed so large in 1972 were almost erased in 1976, because the study says, voters discerned no real difference between Ford and Carter on such questions as busing, legalization of marijuana and women's rights.

With the issue differences blurred on anything but economics, the authors say, voters turned increasingly to Ford's record in office and their historic picture of the Democratic Party for clues to their choice.

The assessment of the incumbent was badly damaged by his pardon of Nixon, which was "a political albatross" Ford never was able entirely to shed.

But the evaluation of Ford improved as the campaign progressed, while the voters' assessment of Carter's capabilities "gradually declined throughout the final six weeks of the campaign."

In the end, however, Ford fell just short of passing Carter on the personal evaluation scale. That failure combined with the greater confidence in a Democrat to handle economic problems, tipped the election to Carter, the Miller's study says.

"The net outcome" of the four televised Ford-Carter debates "provided neither candidate with an enduring campaign advantage," the study says. Some other papers presented at the political science convention disputed this conclusion.

"Evaluations of Ford's ability in the foreign policy area declined significantly following the second debate in which he erroneously stated that Eastern Europe was not under the domination of the Soviet Union," the study says.

"In general, however, the impact of the debates on evaluations was either reinforcing of partisan predispositions or, when contrary to predispositions, short-lived and readily offset by other campaign events."