Once the hoopla is past, the practical impact of the Bakke decision may be that it changes very little - in the short term, at least.

It apparently will do little to change the special policies at about 90 percent of the nation's universities that are designed to increase the number of minority students.

It apparently will do little except reaffirm the validity of "affirmative action" programs administered by 27 different federal agencies and designed to aid blacks and other minority groups.

And the decision leaves similar and controversial programs in private industry in such murky water that the preliminary reading is that most companies will continue much as before.

That was the assessment yesterday from government officials, educators, civil rights lawyers and others close to the issue.

The decision was a politician's dream. It gave almost everyone - Bakke, the government, civil rights groups and most universities - a victory, if a small one.

The medical school at the University of California at Davis was given a slap on the wrist, and told to abandon its special admissions program that reserved 16 slots in each class to members of minority groups. Allan Bakke, who was denied admission by Davis and 12 other medical schools, was given a spot at the Davis school.

But the signals the court gave were confusing.

The key opinion came from Justice Lewis F. Powell Jr., who agreed with four judges on one point - that the Davis program was wrong and that Bakke must be admitted - but with four others on the broader issues of whether race can be used in determining college admissions.

He said race alone couldn't be used, if it were the only consideration. But he said it could be used in combination with other factors, if a university wanted to: eliminate effects of past discrimination; diversify its student body, or to correct an identified problem - finding more doctors, for instance, to serve in black ghettos.

Powell's opinion was considered crucial because it set up standards universities could follow. He specifically cited the admissions policies at Harvard University as meeting these standards - an assertion that drew judicial snickers from other judges.

"The cynical," Justice Harry A. Blackmun said, "may say that under a program such as Harvard's one may accomplish covertly what Davis concedes it does openly."

Spokesmen for civil rights and higher education groups estimated that 90 percent of the existing university affirmative action programs would meet that standard. "We have more programs like Harvard than like Davis," said Jack Peltason, executive director of the American Council on Education. "We have very few programs at the admissions level that won't meet the constitutional standards."

Harvard, like many elite schools, has long had a policy designed to bring certain groups of students onto its campus: sons of alumni, football players, musicians, potential scientists and stockbrokers, and those from states outside its immediate New England area. In recent years, it has added minority groups to these categories.

According to university spokesmen, the entering class at Harvard College next fall will have 8.1 percent of its members black, 5.7 percent Asian-Americans, 4.6 Espanics and 0.4 percent American Indian and forth percent will be sons and daughters of alumni.

The percentage of blacks in the nation's colleges has risen steadily since the mid-1960s. But after making remarkable gains for a decade the black share of enrollment in the nation's undergraduate, law, medical and graduate schools began to drop last year for the first time. It fell from 8.4 percent in 1972 to 7.3 percent last fall.

The drop was even more pronounced in some professional schools. Blacks and other minorities made up 9 percent of the classes entering medical schools last fall, down from 10 percent in 1974. This was despite special admissions programs that made it possible for 41 percent of the blacks and 52 percent of the Hispanics who applied for medical school to be admitted, while only 37 percent of white males were admitted.

These programs have created widespread controversy on campuses across the country where whites claim to have suffered discrimination. Nonetheless, due to a rapid growth in medical and law schools, there are 49 percent more whites in medical schools today than eight years ago and 64 percent more whites in law schools, according to government reports.

In addition, blacks still occupy a disprortionately low proportion of spots in the professions. According to a report by the Institute for the Study of Educational Policy at Howard University, only 0.8 percent of the nation's architects are black, 1.8 percent of its insurance brokers, 1.3 percent of its lawyers, 3.1 of its social scientists, 1.6 percent of its doctors and 1.2 percent of its engineers.

Although the Bakke case brought the entire issue of "reverse discrimination" to national attention, yesterday's decision, according to government officials, will not alter a host of government affirmative action programs.

It also didn't answer a series of issues that have created increasing tension in recent years between government and industry, including six now sitting before the Supreme Court.

One case, for example, involves a requirement in the Public Works Employment Act of 1977 that 10 percent of the billions of dollars of grants made under the law be spent for minority businessmen.

Another deals with what one judge termed "the largest and most impressive civil rights settlement in the history of this nation," a case in which American Telephone & Telegraph Co. agreed to a stiff affirmative action program now challenged by union members.

The business community, by and large, took a wait-and-see attitude yesterday. General Motors and DuPont, for instance, said they didn't plan to revise any of their affirmative action hiring programs as a result of the Bakke decision.

For those businesses wishing to avoid setting up affirmative actions programs, the Bakke ruling may give them a reason not to do it now, said Earl Graves, owner and publisher of Black Enterprises Magazine in New York.

But major corporations are not about to do a "180 degree turn," he added. "At the highest level, there is no question that the leadership of corporate America sees that doing business with minorities is not only right, but profitable."