The rise in the unemployment rate, from 8.4 percent in July, reflects an increase in the number of people looking for work in the city, said Barbara Byrne Denham, a private economist who analyzes the official data issued every month by the State Labor Department.
Ms. Denham estimated that employers in the city added 10,200 jobs last month, bringing the total gain for the year so far to nearly 85,000 jobs. The city is on pace to add at least 100,000 jobs in 2013, she said, the biggest increase in a year since 1999.
“The good news is the gains were really across the board,” said Ms. Denham, who works for Eastern Consolidated, a real estate services firm in Manhattan. Ms. Denham performs her own calculations to adjust the Labor Department’s figures for seasonal fluctuations in hiring and firing. The department seasonally adjusts the statewide jobs data, but not the city numbers.
The persistently high unemployment rate has bedeviled Mayor Michael R. Bloomberg and other city officials. On Tuesday, one of Mr. Bloomberg’s deputies, Robert K. Steel, appeared on CNBC to trumpet the strength of the city’s economy. He said the city had gained back twice as many jobs as it lost during the financial crisis that started five years ago.
Ms. Denham agreed with those numbers. By her count, the city lost about 165,000 jobs in the recession, but gained back all of them plus an additional 150,000 jobs.
She too discounted the rising unemployment rate, attributing it to an increase in the number of New Yorkers encouraged about the prospects for finding jobs. The labor force tends to grow when the economy gains steam and hopes of getting hired rise; people without jobs count as unemployed only when they are actively looking for one.
“I think there’s a lot more optimism in the economy,” Ms. Denham said.
Wall Street, which has traditionally led the city’s economy out of recessions, was an exception to the positive trend in August. The securities industry lost about 1,700 jobs last month, leaving it with a net loss so far this year, Ms. Denham said.
Elena Volovelsky, an economist with the State Labor Department, said the number of jobs in computer systems design and advertising in the city rose to “all-time employment highs” in August. She said that the financial industries were weak, but that some of those job losses could have resulted from summer interns’ returning to school.
Statewide, the number of private-sector jobs increased by 22,700 in August, the department reported. The state’s unemployment rate also rose, to 7.6 percent last month from 7.5 percent in July. The national unemployment rate is lower, at 7.3 percent for August.
In New Jersey last month, the numbers moved in the opposite direction: the state lost jobs, but its unemployment rate dipped. The Department of Labor and Workforce Development reported on Thursday that the state’s unemployment rate declined to 8.5 percent in August, from 8.6 percent in July. But it also said that the number of jobs in the state declined by 1,500, making for a two-month loss since June of 12,000 jobs.
According to the official definitions, there were about 392,000 unemployed residents of New Jersey and more than 730,000 in New York State, about half of which lived in New York City.