One year after a Greater Washington Research Center study found that blacks are underrepresented in executive and professional jobs in metropolitan Washington, the Montgomery chapter of the NAACP has dropped the other shoe.

A recent NAACP survey of 142 public companies in the area found that blacks and women are "virtually excluded" from corporate boardrooms.

The NAACP survey found that nearly 95 percent of all seats on corporate boards in the area are held by white males, a situation that the organization cited as a "contributing factor" to continuing discrimination in the marketplace.

Although the NAACP survey was conducted independently, it is, in a sense, an extension of the more scientific findings contained in a January 1985 Greater Washington Research Center study titled, "The Washington Labor Force: An Asset in a Changing Economy."

The earlier study, which was conducted for the center by economic consultants George and Eunice Grier, documented the existence of a wide gap between blacks and whites in the area's labor force. The authors found that black males are "the most seriously underrepresented" of all groups in executive and professional jobs, and that the occupational gap "remains large, even for those with college training, although it is reduced for women of both black and white races."

An apparent inability of black males, even those with college or graduate-school educations, to obtain jobs commensurate with their educational achievements "mars an otherwise exemplary labor-force picture," the Griers concluded.

The findings in the GWRC study and the more recent NAACP survey are remarkably similar and revealing. What they say about corporate metropolitan Washington is instructive.

Whether this latest assault on an entrenched old-boy system will make a difference remains to be seen.

For years, individuals as well as small groups of stockholders have raised the issue at annual meetings, only to be told that sincere efforts were being made to find "qualified" minorities and women to serve as directors.

A few Washington-area companies, especially utilities and the bigger D.C. banks, have made good on those promises over the past decade.

Ironically, District banks have come under increasing pressure in recent months to appoint blacks and women to their boards, as local officials seek to make that a condition for approval of interstate merger applications.

Elected officials have no such leverage, however, to force most other public companies to change the racial and gender makeup of their boards.

NAACP officials say they intend to ask legislators in the respective jurisdictions to create a blue-ribbon panel to study the problem, and they will ask U.S. agencies to investigate the matter. In the absence of any legal mandate to force changes, even those steps are likely to fall short of accomplishing the NAACP's goal.

Except in those cases where there is evidence of equal employment opportunity violations, government officials can do little about corporate decisions affecting promotions and appointments.

The publicity from investigations and hearings may cause some embarrassment, but companies aren't likely to alter their guidelines for selecting board members as long as sales and profits aren't affected.

Typically, people are elected to boards because of their perceived ability to bring new business to a company. In some cases, the presence of certain board members is thought to add to a company's prestige.

Frequently, people are appointed as directors because their companies own substantial amounts of stock in firms on whose boards they sit. In other cases, membership on boards can be traced directly to more mundane qualifications, such as friendship and membership in white male-dominated clubs.

Perhaps the NAACP can persuade some companies to consider the dynamics of the marketplace and the impact it could have on appointments to boards. Put another way, perhaps the NAACP can achieve better results by enlightening corporate executives about the marketplace. As a starter, the NAACP might refer certain corporate executives and directors to another set of findings that the GWRC assembled last year.

"By any standard of comparison," the research center said in its October newsletter, " metropolitan Washington is one of the nation's most important black consumer markets." Enough blacks have achieved middle to upper incomes "to constitute a consumer market that should not be ignored," the study said.

It's hard to imagine that qualified professionals and executives can't be found in that market. The more enlightened companies have managed, somehow, to find them and put them on their boards.