In some U.S. states, nearly half of the job seekers who have stopped looking for work have done so because they simply don't believe they'll find anything. Indeed, the number of discouraged workers nationwide has more than doubled in the past year. This trend won't be reflected in the widely publicized unemployment rate, as discouraged workers aren't included among the unemployed. Still, in states as diverse as Mississippi, South Dakota, and New York, the span of this often invisible slice of workers signals a population losing its hope.

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Most jobless people who have stopped looking for work are otherwise engaged—they're back in school, taking on family responsibilities, or too sick to search. They, along with workers who have stopped because they're discouraged, make up a group that the Labor Department calls the "marginally attached." They're included in some of the broader measures of unemployment, but they're officially not part of the workforce. While discouraged workers make up about a third of the marginally attached nationwide, their numbers have been increasing.

Between the third quarter of last year and the second quarter of this year, Mississippi averaged the highest percentage of discouraged job seekers among its marginally attached—nearly 50 percent, compared with 32.6 percent nationwide. South Dakota ranked second after Mississippi, with 48.5 percent of marginally attached workers classified as discouraged. Florida, Michigan, Connecticut, West Virginia, and New York followed in ranking for the highest rates of discouragement.

Discouraged workers are characterized by their perceptions. They don't think work is available for them, or they believe they lack the necessary training to be hired. They may be convinced that employers think they're too young or too old, or they believe that they face some other kind of discrimination that prevents them from finding work. And while there are discouraged workers in healthy economies, in a prolonged recession such as this one, worker pessimism tends to skyrocket.

The heights of discouragement in Mississippi are significant. "It says something about the situation in that state when half of the people with a relatively recent commitment to searching for a job have stopped because they believe nothing is available for them," says Thomas Krolik, an economist at the Bureau of Labor Statistics. Between the third quarter of last year and the second quarter of this year, Mississippi's average unemployment rate was 7.9 percent. Add in all the discouraged workers, and the rate shoots up to 8.8 percent, a 0.9 percentage-point jump. Nationwide, the average difference between the unemployment rate and the rate of unemployed plus discouraged workers was about 0.4 percentage point. Michigan and New York also ranked high by that measure.

Charles Campbell, a professor of economics at Mississippi State University, says the state struggles with regions of particularly high unemployment, "where there really are no jobs." Many of the residents of those regions lack the skills and means to find work in outside areas, Campbell says, so they remain unemployed.

In other states, the situation may be more obvious. In Michigan, the demise of the domestic auto industry has brought job destruction far outpacing the national average. Michigan's unemployment rate for June topped 15.2 percent, compared with 9.5 percent nationally. Across the country, Florida has been hit hard by the housing bust, and unemployment in the state reached 10.6 percent in June.

But higher unemployment rates and lousier job markets alone don't explain the high rates of discouragement. Connecticut, New York, and West Virginia have seen their numbers of jobless workers rise during the downturn, but their unemployment rates are all below the national average.

Several things could nudge job seekers toward hopelessness: negative media coverage of the job market; unsuccessful job searches among friends and family; their own long-term unemployment. Also, men are more likely to give up their job search because they've become discouraged—they make up 63 percent of the total group. Younger workers, blacks, and Hispanics are also overrepresented in the discouraged-worker category, according to the Labor Department.

The housing bust could be partly to blame. Workers may simply give up because there are no openings matching their skill set within their geographical area, Krolik says. If workers own homes they can't sell, their ability to move for a new job is severely limited. The effect could be exacerbated by areas where homes are a particularly difficult sell or homeowners are disproportionately underwater, as those markets have also tended to see higher unemployment rates.