The results of a recent Washington Post election campaign poll produced mixed signals for incumbent D.C. Mayor Marion Barry on the issues of jobs and commercial development.

Those issues aren't likely to determine the outcome of the Democratic primary, but Barry hasn't delivered on his promise to make economic development a showcase of his administration, the poll clearly indicates.

The fact that a majority of voters apparently isn't aware of efforts to improve the economic climate of the city is of concern to some in the Barry administration. Aides are optimistic, nevertheless, that plans being prepared now will prove Barry's promises of jobs and economic growth to be more than just mere rhetoric.

Little more than a third of the 1,374 registered Democrats interviewed in the poll believe that Barry would do a better job of creating jobs and stimulating downtown development.

Only 35 percent believe Barry would attract more jobs for District residents, compared with 26 percent for Patricia Harris, his chief opponent. Another 39 percent either have no opinion or lean toward other candidates.

And while voters feel that Barry and not Harris can stimulate downtown growth (38 percent to 25 percent), 37 percent showed no support for the mayor on that issue.

Long before he announced his decision to run for re-election, Barry launched a major campaign last year to call attention to a boom in downtown development and what he described as a "litany of things that have happened since I've been mayor."

It's obvious that the District's economy has benefited from a surge of private, nonresidential construction. But that surge began at least five years ago--before Barry became mayor.

Indeed, a momentum that began in 1977 has continued almost unabated until recently, and it mattered little who sat in the mayor's office.

The only major public construction project that has generated substantial numbers of jobs during Barry's administration is the convention center. And except for the promise of jobs to District residents as a result of a couple of firms relocating here, the city itself has not created large numbers of jobs.

Commercial construction increased 182.8 percent from $60.5 million in 1977 to $171.2 million in 1980. Most of that growth occurred in office building construction, according to a study completed last year by Brimmer & Co. Inc., economic and financial consultants.

Stimulated primarily by strong demand from trade and professional associations, accountants and law firms, office space in downtown Washington grew by more than 5 million square feet in the past two years and is expected to increase another 3 million square feet, at least, by the end of the current year.

Although the construction boom and a resurgence in the services industry were triggered and sustained by the private sector, Barry was quick to credit these visible signs of economic growth to his leadership. He attributed investor interest in the District to "a new atmosphere of confidence" created by his administration.

But comments by developers of several major projects show that an enormous demand for office space, completion of Metro, and the impetus provided by the Pennsylvania Avenue Development Corp. and start of construction on the convention center solidified investor confidence in the District.

Concerned that District residents were unaware of his administration's role in producing a better economic climate, Barry last fall launched a carefully orchestrated campaign to make his point.

Almost overnight, signs proclaiming "D.C. on the Grow" were plastered on practically every major commercial construction project downtown. The campaign was started officially with the mayor leading a tour of the projects for business leaders and elected officials.

But that kind of public relations hoopla hasn't produced the jobs that the private sector has through commercial development. And that fact apparently hasn't been lost on local residents.

"I would be inclined to consider that the percentage of people that have no opinion are unaware of what's happening," observed Lawrence P. Schumake III, executive director of the District's Office of Business and Economic Development.

Schumake maintains that it has taken a while for some things to "evolve" and that they "haven't touched a lot of people."

He cited two major areas that should soon produce plans for generating jobs and enhancing commercial growth. The first of those, he said, is the comprehensive plan for downtown, a process that has been described as vital for revitalization.

The second major plan is being prepared as a legislative proposal for establishing incentive zones in industrial areas. The aim here is to revitalize delapidated commercial areas such as the New York Avenue corridor by offering inducements, including tax incentives, industrial revenue bonds and loan programs.

Plans such as those provide a basis for optimism over the next year, Schumake believes.