WHEN PRESIDENT BOK suggested last spring that the Business School should de-emphasize its use of the "case method," faculty members and students across the river rushed vigorously to the defense. The standard they raised to rally support for the school's teaching techniques, however, is a barely visible one: no two people can ever be sure that they are talking about the same thing when they use the phrase "case method."

Perhaps the best way to sharpen that vocabulary is to look directly at the kinds of "teaching" presently used at the Business School under the loose rubric of the "case method."

The one characteristic that links all "case method" classes together is, obviously, their use of cases as illustrations of a source for class study. A case is a set of facts or circumstances adopted from real life business situations for use as a tool for business analysis. A case can be a copiously researched paper or a small drama; it can flood students with data or can leave them searching for more. The forms a case can take seem limited only by the aim and ability of the professor researching and presenting it.

Further, a professor can, if he desires, supplement his case with background papers, lectures, articles or films on theories of business. Or, he can let the case stand alone.

Even in courses where the case and support materials are similar, there is a tremendous diversity of approach among teachers all professing to be using the same "method." A paper issued in 1977 by Arch R. Dooley, Philips Professor of Manufacturing, and C. Wickham Skinner, Robison Professor of Business Administration, stresses just that diversity. The report, called "Casing Case Method Methods," claims that "the phrase 'case method' embraces such an array of pedagogic practices that the term itself has no precise connotation."

The "array" they refer to is largely a range of degrees to which different professors offer their classes direction in discussing and analyzing the situations outlined in their classes.

Styles of class leading vary considerably. In the "classical" case method technique (though few if any B-School professors could be placed easily in this category), the professor sits back and lets the students discuss the various facets of the case on their own. He offers no guidance or insight, trusting the students to learn from one another.

At the other end of the spectrum is the professor who uses the case strictly as a background, an illustration, for his classroom lecturing. He entertains little student comment and makes all the major points of each case clearly.

BY FAR THE MOST POPULAR teaching style at the B-School, however, is a middle-of-the-road one. The professor guides and gives focus to his class through careful questioning and directing student discussion toward major issues. He might summarize key points or areas of conflict, but is reluctant to burst forth with "right" answers.

Different modes of instruction are often used for teaching different topics. "Where knowledge is systematic, you might as well let them have it directly," Renato Tagiuri, professor of Organizational Behavior, says. "Don't waste time discussing, getting them to re-invent the wheel." Interactive, student-centered teaching, Tagiuri feels, is most useful in areas where knowledge is more open to debate.

John J. Gabarro, professor of Organizational Behavior also feels that some systemized knowledge is best taught through lecture or through problem sets "disguised as miniature cases." But, he adds, there is a trade-off made in gaining the efficiency of a lecture and losing the student active student participation of a case discussion.

"For the conveyance of sheer information and theory and concepts, the case method is not the most efficient method," Gabarro said. "But it is highly effective in the sense that concepts, ideas, approaches and theories are thoroughly grounded and far more internalized."

Dean W. Currie, Assistant Dean for Educational Affairs, agrees that the interactional case approach is more effective than straight lecturing in internalizing knowledge. "It's a Zen Buddhist-like belief that there is wisdom that can be learned but can't be told," Currie says. Students gain that wisdom by closely involving themselves with the cases presented, and actively participating in discussions that locate and solve problems, he adds.

"You retain a tool better if you've used it. No matter how often you look at a hammer, you can't claim craftsmanship with it until you've pounded a few nails," according to the Dean.

THE B-SCHOOL's case method, then, has its advantages. It is flexible--students report differences in the use of cases from area to area, with cut-and-dried course materials like elementary accounting being treated largely in lectures, while interactive discussions deal with more nebulous questions. Teaching styles, case complexity and support materials vary widely from professor to professor and even from class to class.

But the case method has its disadvantages, as well. Discussion courses do move through material more slowly than do traditional lecture courses--Harvard B-School courses are among the longest, in hours, in the nation. Further, the constant researching of cases from companies and public sources to provide new, realistic cases for student examination is tremendous investment in time for each faculty member, and investment in money for the school, which spends nearly $6 million annually for case research alone.

Finally, perhaps the worst disadvantage of the case method is the widesperad misunderstanding of its components and its flexibility. "There is no single doctrinaire thing called the case method," George C. Lodge, professor of Business Administration, said last week. "There is no dogma."

Without any uniformly agreed upon vision of the case method, the whole controversy over how widely the B-School should use it shrinks in importance. If one man's "case analysis" is another's academic discussion, then arguing for or against emphasis on the case method is an exercise in imprecision.