For 12 years, Quinn Smith worked as mailroom supervisor for the Broadway impresarios the Shubert Organization.

He brought home about $28,000 a year and was making good on his bills and on child-support payments for his daughter. That routine ended last February, when Mr. Smith, a high school graduate who also has three years of college under his belt, was laid off.

Although the 43-year-old resident of the Queensbridge Houses, America’s largest public-housing development, found a part-time job this spring as a maintenance worker making $7.50 an hour, he has yet to find full-time employment.

“I got my foot in the door with Verizon, Con Edison, and FedEx,” he said during a recent interview, sitting on the steps of the brightly painted community center where he works. “I’m waiting. It’s just a waiting game.”

Until April, Mr. Smith was one of hundreds of thousands of black men in the city without a full-time or part-time job. It’s an economic and social problem that Mayor Bloomberg’s Democratic challengers have tried to capitalize on as they’ve made the case that the mayor does not merit a second term in City Hall.

On Martin Luther King Jr. Day, in front of several predominantly black audiences, one of the four Democratic mayoral contenders, Gifford Miller, the City Council speaker, cited the alarming statistic that 49% of black men in the city didn’t have jobs.

Mr. Miller, who still regularly refers to that number in front of community groups, said the dip in the city’s official unemployment rate did not tell the whole story.

“The government will tell you that the unemployment rate is at a low, 6%, 5%,” he told the crowd at the Brooklyn Academy of Music in January.

“But,” Mr. Miller said, “49% of African-American men in this city do not have a job. And what I find more troubling than that statistic is the silence of our leaders in response.”

The figure Mr. Miller cited appeared in a study published last year by the nonprofit and nonpartisan Community Service Society, which focused on the percentage of residents without jobs rather than on the official unemployment rate – a tally that excludes anyone who isn’t looking for work.

An updated report, however, found significant job gains across the board. Released in February, it said that last year, during the economic upswing, black men in the city gained more jobs than any other group. The new figures show a gain of more than 9 percentage points in 2004, leaving 39.3% of black men without jobs, compared to the 48.8% in 2003 that Mr. Miller and others had been rounding off.

Some followers of the issue said the Community Service Society’s numbers are inflated because they include anyone above age 16 who is working, including full-time students and others who do not want to be counted among the labor force. By comparison, the U.S. Bureau of Labor Statistics found that in 2004 overall unemployment in the city improved to 7.1% from 8.4%.

According to the regional commissioner of the government bureau, Michael Dolfman, a breakdown revealed that the rate was at 6% among whites, 8.3% among Hispanics, and 11% among black residents (of both sexes).

Still, economists of all persuasions said that no matter which statistics are used, the gap between the black working population and the Hispanic and white populations is indisputably wide. Further, Mr. Dolfman said, black teenagers in the city have “one of the highest unemployment rates in the country.”

The senior policy analyst at the Community Service Society, Mark Levitan, acknowledged the dramatic gains that his more recent study found for black men. At the same time, he said that population is often more prone than others to economic swings. When the economy contracts, as it did four years ago, it is often black men who are the first to lose jobs, and when it expands, they tend to gain at slightly higher rates.

“If you smooth out a couple of these outsized year-to-year changes, what you see is a picture of growing disadvantage,” Mr. Levitan said. “One good year really doesn’t change that story.”

Mr. Levitan points to what his report calls a “steady erosion” of the number of black men with jobs. According to his research, in the early 1990s, black men in the five boroughs were 14.6 percentage points behind white men in terms of holding jobs. That percentage spiked to 19.9 percentage points in 2003-04.

Mr. Levitan attributed the sharp swing that his study found for the past two years to a combination of factors, including the study’s margin of error, which is plus or minus four percentage points; recent population adjustments made by the federal government, and overall changes in the economy. While the swings did exist, they may have been exaggerated, Mr. Levitan’s report concluded.

Nonetheless, the issue of unemployment and “job creation” tends to be an attention-grabbing election-year topic, and this year is no different.

Last month, 10 members of the City Council’s minority caucus stood with Mr. Miller and executives from the nonprofit charitable consortium the United Way to announce a search for a company to run a $10-million job-training program. The program would build upon an initiative started by the council last year, which also earmarked $10 million.

A Brooklyn Democrat on the council, Charles Barron, said the council’s investment was a positive step, but the funds were a “drop in the bucket” for a city with a budget of $49 billion.

“We should be reprioritizing,” Mr. Barron, who himself mounted a short-lived mayoral campaign, said just before the news conference. “The mayor should be doing more, not bragging that we have a low unemployment rate. What are we, invisible? What, is this Ralph Ellison again?” Ellison wrote “Invisible Man” a half-century ago about the plight of many African-American males.

Mr. Barron’s criticism notwithstanding, Mr. Bloomberg has painted himself as the shrewd business executive who steered the city through one of its most difficult economic periods.

The mayor regularly talks about how the city is adding jobs under his stewardship, and officials of his administration cite a laundry list of programs created to tackle the disparities that put members of minority groups at a particular disadvantage.

The deputy mayor for policy, Dennis Walcott, said the administration’s focus on improving the city’s public schools, whose enrollment includes a disproportionately high percentage of minority students, is a crucial part of its plan.

Mr. Walcott, who is black, also cited the three-month-old Mayor’s Commission on Construction Opportunity, which is exploring ways to link residents, particularly minorities and women, with jobs in the industry.

For months, Mr. Bloomberg said his proposed Olympic stadium for Manhattan’s West Side would be a boon for job growth. That plan was blocked by a state board this month, but the Bloomberg administration announced last week new deals to help the Mets and Yankees build new baseball stadiums, with the Mets’ facility in Queens to double as the main venue for the 2012 Summer Games should New York be named host city.

Still, Mr. Bloomberg’s political challengers have said the mayor should be doing more to promote job growth. The Democratic mayoral front-runner, Fernando Ferrer, has said New Yorkers are not looking for jobs selling Cracker Jacks, but for skilled work that will allow them to start careers.

At the Queensbridge Houses, a complex of 96 stout red-brick apartment buildings where Quinn Smith lives, the percentage of residents without jobs seems high. The few commercial strips are rundown, the schools have lagging tests scores, the average household income is below $20,000, and just a few months ago, federal and city authorities arrested 37 people in a drug-dealing sting.

The Reverend Mitchell Taylor, founder and president of a nonprofit organization called the East River Development Alliance and a pastor at the Center of Hope International, a nondenominational church, said the area had been “overlooked and underserved” for years and the “concentrated poverty” makes it difficult for residents to shatter their existing conditions.

His organization was established to connect residents in several public housing developments to the surge of businesses down Vernon Boulevard, less than a mile from Queensbridge. The alliance has forged partnerships with local businesses to provide job training in commercial truck driving, retail, and computer science, among other fields.

“It’s all about connecting good people to employers,” Rev. Taylor said. “I say that because for a long time, Queensbridge was probably looked at as a place that you would not want to get employees. If you really check the records … you don’t see a lot of hires for 11101.”

Rev. Taylor said he is pleased with the city investments and hopes that more resources will be devoted to creating new job opportunities for those who need them most. The council member whose district includes Queensbridge, Eric Gioia, has helped connect the alliance to various companies, provided city financing, and kept the organization abreast of different programs, such as the earned income tax credit, that its clientele can take advantage of.

“What’s important is that as the economy grows that everyone shares in the prosperity,” Mr. Gioia said. “It is unsustainable to a city of haves and have nots. In Queensbridge you have a stark delineation. On one side of the Queensboro Bridge, you have Long Island City, which is thriving and has Fortune 500 companies investing. On the other side, you have the biggest housing development in America.”

One of the men the alliance has helped is William Collier, who grew up in the Bronx but now lives in Queensbridge with his wife and son. He served six years in prison upstate for criminal possession of crack cocaine with intent to sell. Collier, 44, who dropped out of the 10th grade, earned his high-school diploma in prison and said he has since turned his life around.

It took him more than a year of job rejections, mostly from department stores and factories, before he found a job loading trucks from the now-popular mobile supermarket Fresh Direct.

“It feels good,” he said. “I’m getting up and doing something with my life. It motivates me to have a job and to be responsible.”

The borough president of Manhattan, C. Virginia Fields, another of the Democratic contenders and the only black candidate in the mayoral campaign, said the two issues she is asked about the most are jobs and housing. Though Ms. Fields has not outlined detailed plans as some of the candidates have, she has said that if elected, she would establish a full-time deputy mayor of employment.

“As the late Adam Clayton Powell said, the only way or the best way to deal with poverty is to get people to work and put money in their pockets,” she said, referring to the longtime congressman from her home district in Harlem.