Accounting for those adjustments, the labor force had a net gain of 250,000 people in January from a month earlier. Although the pool of unemployed people has been shrinking, the number remains high — 12.8 million — about equal to the population of Pennsylvania, and long-term unemployment is one of the most crushing legacies of this recent recession. For January, the Labor Department reported that 5.5 million people had been out of work for six months or more, about 43 percent of the jobless.

And according to an analysis of December’s job numbers released this week by the Pew Fiscal Analysis Initiative, nearly a third of the jobless have been unemployed for a year or more.

Underemployment is another stubborn problem. The number of people working part time because they cannot find full-time work was 8.2 million in January. Including that group and the 1.1 million who stopped looking for work altogether, and the broader measure of unemployment was 15.1 percent.

“You have an interesting situation where you have some permanent part-time workers,” said John Silvia, chief economist at Wells Fargo. “These people are in jobs and the jobs are not likely to become full time.”

Sandy Pochapin, a 54-year-old former marketing manager, was laid off for the second time last May from a small business in Newton, Mass. Just before the start of the year she picked up a part-time job as a media consultant at an advertising agency. Her husband, a real estate lawyer, has also experienced severe cutbacks in his income.

The couple, who are now paying three times what they were paying for health care before Ms. Pochapin lost her job, have cut back on dinners out, and she said that replacing her eight-year-old Toyota Highlander was “not in the cards.” More painfully, the couple have dipped into their college-age son’s educational fund to keep up with mortgage payments and other expenses.

Ms. Pochapin, a member of several networking groups, compiles job leads and recently sent out a list with more openings than she had ever seen. “I would say things are picking up,” she said. “But where they’re picking up is not where people who have been unemployed long term have skills.” She noted many openings for jobs in mobile marketing and for digital media specialists.