By his own account, Otis H. Troupe, the new city auditor, is one of the ''three senior-most'' officials in the District of Columbia -- ranking in the stature with the mayor and the chairman of the City Council.

But in the five-and-one-half months since the City Council confirmed his nomination, Troupe has yet to exert the wide-ranging influence on city affairs of his predecessor, Matthew S. Watson.

Troupe, 36, is the only official in the city with authority to scrutinize the operations and performance of any D.C. government agency or employe. His reports will be read by the mayor, City Council, Congress and the public. So far, however, he has completed only one audit and begun a handful of reports. And he has avoided the media spotlight that shone regularly upon Watson, and that is generally considered the job's main source of clout.

"It is very gratifying to me that the office has escaped a great deal of intense scrutiny," said Troupe, sitting behind a large desk in his office at 415 12th St. NW. "Basically, it's just not a political office. Our primary function is to act as an independent observer, consultant, evaluator for both operational and financial activities of this city."

Troupe says his activities during the last few months reflect that mandate. He has completed one audit -- of a sale by the D.C. Development Corp. -- made at the request of Council Member David Clarke (D-Ward 3) and released without fanfare in May. In April he reviewed the supplement to the city's 1981 budget. When he examined the amendment to the 1982 budget in June, he balked briefly at the mayor's decision to borrow $40 million from the U.S. Treasury, but backed down, he said, when he received "adequate information."

Troupe said he has met with most City Council members to express his willingness to undertake projects of interest to them. Accordingly, he has begun investigations of that legislative phoenix, the municipal bond issue, and for Chairman Arrington Dixon, a report on cable TV.

There are other investigations, said Troupe, "that I am not at liberty to discuss."

Troupe's preference for the quiet route stands in stark contrast to the style of his predecessor. Watson, a former attorney for the General Accounting Office, became the first person to hold the job when it was created under the Home Rule Act of 1973. The act simply requires the auditor to do "a thorough audit" each year of the "accounts and operations of the government of the District."

But when Watson took office in February 1975, he quickly made headlines for his trenchant analyses of issues ranging from foster care to income from rental cars to nepotism in government hiring. He avoided what he called "green eye-shade audits" -- scrutinizing the bureaucracy for minor improprieties; instead, he preferred to play the consultant's role by pointing out problems and suggesting specific solutions.

And although Watson vowed to avoid an adversarial stance toward other branches of government, he was, nevertheless, famous for the contentiousness that his gentle demeanor belied.

"Matt loved controversy . . . but he was a cheerful fighter," said Virginia Fleming, executive assistant to City Administrator Elijah Rogers. Her opinion was widely shared among officials who, like her, had to respond to Watson's reports chronicling waste, inefficiency, wrong -- and sometimes, right -- doing in city agencies.

"We may have quarreled with his recommendations or solutions but we never -- as far as I can tell without checking on it -- we never quarreled that the facts were incorrect," Fleming said. D.C. Budget Director Gladys W. Mack said, "Of course we differed on some things but for the most part, on financial matters, his thinking was pretty consistent with the thinking of this office."

Troupe, meanwhile, has impressed observers with his credentials, if not his image. A native of the District's Petworth neighborhood, Troupe attended McKinley High School and graduated two years after Arrington Dixon, now council chairman. Their fathers played golf together at Langston Field, Troupe remembered. Troupe received his bachelor's degree from Yale University in 1966 and a law degree from Boston College Law School in 1970, though he did not take the bar exam in New York until 1977. He has yet to be sworn in by the New York Bar. He also attended Columbia Business School.

His past positions were: director of the Harlem Commonwealth Technical Assistance Center, market planner and analyst for Exxon International in New York, and acting vice president for the Bedford Stuyvesant Restoration Corp. He worked for the U.S. Comptroller of Currency as a financial analyst for 15 months before taking over the auditor's job.

Dixon said he selected Troupe because "he brings together both the accounting, financial and legal backgrounds with his training and work experience. Plus Otis had worked in other cities in areas of economic development in the corporate world."

But most importantly, said Dixon, "Otis' commitment to the city is very, very deep. He's a many generations Washingtonian. I've known him through childhood, through his family, and I know their commitment to the city." That family includes Troupe's aunt, Marjorie H. Parker, chairwoman of the Board of Trustees of the University of the District of Columbia and the wife of U.S. District Court Judge Barrington D. Parker. The connection, said Dixon, had nothing to do with Troupe's appointment. But it shows "that he has some very deep roots in the community."

Beyond a 60-day stint as Dixon's budget analyst last winter, however, Troupe has no experience in District affairs. While Dixon said he purposely chose a government outsider for his "fresh perspective," critics of the appointment insist that at least a passing familiarity with District officials and issues is important for an auditor because the staff is too small and the workload too vast to allow time to flounder.

"I'm a little concerned that he's been there several months and only produced one audit," said a former staff member in Watson's office who requested anonymity. "I think he might be a McClellan, you know, the Civil War general who marched his troops up and down the Potomac," without ever moving in for the attack, he said.

Critics also are concerned that his connections may make him less aggressive in his job, and they worry about Troupe's stated preference for the backstage. As another former employe of Watson's office said, "The D.C. Auditor is the only city agency who can walk into the mayor's office and say, 'That desk is city property and I want to see what's in it.' And he needs no summons, no warrant, no subpoena. It's a powerful right and we defended it fiercely."

"What good is it being the D.C Auditor," added the former employe, "If you're going to be low profile? There are only two powers the city auditor has. Number one is to refuse to certify revenue estimates for a bond sale. But the second, most important, power is the power to embarrass stupid, inefficient, wasteful government. And we did."

But Troupe insists that being confrontational has nothing to do with being useful. He says he will put his own stamp on the office by focusing less on the "operational side," which Watson favored, and emphasizing financial issues. He also vows to avoid an adversarial relationship with the executive branch, and wants to enhance the "research capability" of the office.

"I'd like the city auditor's office to have an approach which says that, as an objective auditor, we'd like to evaluate your successes and operating system in accordance with generally accepted principles," he said.

"Matt was a lawyer; I have a business background," Troupe continued. "We want to become more active in the field of financial analysis. We think that's necessary at this time (because) if you look at what the District is planning in the next two years, most milestones are economic or financial. We're talking about entering the municipal securities, we're talking about cable TV."

Only three of Watson's professional staff of seven had accounting backgrounds, and although Troupe lost more than half of Watson's staff, he has yet to fill most of the positions. Troupe also lost more than $60,000 of the office's $363,400 budget in an austerity measure. Thus, says his deputy, Harold Walker, who also worked for four months in Watson's office, "You cannot compare the two, when one person has held a job for six years and another for six months. You will see interesting things coming out of the auditor's office."