The standardized tests given by Educational Testing Service for college admission and other purposes fail to predict how well students will do, exclude disproportionate numbers of minority students, and perpetuate "a class system in the guise of merit," according to a report released today by Ralph Nader.

Both Nadar and Altan Nairn, the report's principal author, stopped short of recommending that the tests be abolished, but asserted that the way the tests are used by college admissions officers and the claims made for them by ETS "are clearly untenable."

"The claim that these tests measure aptitude and predict performance, the use of these tests to determine who can get into schools and professions clearly cannot be justified by the evidence," Nairn said at one of a series of briefings and news conferences he and Nadar have given over the past several days to introduce the report.

"We call for a fundamental reexamination on the part of colleges and consumers of the claims ETS makes about their tests," he said, and public debate on "how to construct an alternative test system which has a sounder basis . . . and which opens things up for more people."

ETS President William W. Turnbull termed the report "an anticlimax."

"The report's major criticisms and conclusions appear to date from the May 1975 issue of the Ladies Home Journal, in a Nadar article published before the 'study' began. It is clear that the verdict was in long before the trial started," he said.

He charged that Nader has been on "a crusade" against ETS type testing, "and the statistics in this report are part and parcel of that."

The 550-page report, entitled "The Reign of ETS: The Corporation That Makes Up Minds," was begun in 1974 when Nairn, now a 24-year-old Columbia undergraduate, was a high school senior. Nader said his investigator's youth was not a drawback but instead gave him a broader, consumer-oriented perspective.

The report's principal charges against ETS are:

That while the testing organization touts its exams as predictors of how students will do in school, there is little correlation between test scores and college grades. In fact, "90 percent of the time tests predict first-year grades no better than a random process such as a roll of the dice."

That the tests exclude "a disporportionate number of minority applicants who are capable of succeeding" in school.

That test scores correlate directly with family income, while college grades and accomplishments do not."We are dealing here with a very sophisticated testing systems that perpetuates class distinctions in the name, ironically, of meritocracy," Nader said.

Because they are the key that opens so many doors, the tests "distort" both school curricula and students' views of what is important.

Nader was quick to say that he is not against standards per se. "Any society that appreciates mobility has got to have standards of evaluation, and the question is not whether there should or shouldn't be standards of evaluation; the question is what kind of standards, who can review them, who can verify them, who can challenge them . . .," he said.

ETS, the largest testing company in the country, is a private, nonprofit organization based in Princeton, N.J. With a budget in excess of $90 million and a permanent staff of 2,300, it devises and administers tests to some 7 million people each year on topics ranging from general verbal and mathematical skills (the Scholastic Aptitude Tests, or SATs, and Graduate Record Exams), law and business to such diverse occupational skills as firefighters and CIA employes.

Nadar attributed the popularity of the tests with admissions officers to the fact that it is "an easy measure." The tests "have status and prestige," and the result "is a number -- it's superficially precise."

He charged that many institutions use a cutoff score -- such as 500 on the Law School Aptitude Test -- below which applicants are not even considered, whatever their other achievements. Thus "people are struck out of opportunities in educational career areas on the basis of a three-hour test." That, he said, is a "consumer fraud."

ETS' Turnbull countered that "of course" test scores correlate with family income, but unfortunately "there are very few things in this society that involve academic achievement . . . that do not correlate with family income."

The poorer scores of poorer children reflect failings in their education, he said. ETS tests "do not create the difference, they reveal it," he said. h

Turnbull also called the report's statistics "misleading," and asserted that the bulk of the research his organization has done or knows about shows that the tests are valid predictors of academic performance.