En español | Michelle Chesney-Offutt, 54, had been out of work for about a year when she got a call from a recruiter seeking someone with help-desk skills.

At first, the headhunter told her she was a great match, but when he realized she had been out of work for a full year (and not newly unemployed as he had mistakenly assumed), he changed his tune. Company criteria ruled out applicants who had been unemployed for more than six months, he told her. "He was very apologetic," says Chesney-Offutt, who lives in Sandwich, Ill.

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"Once they become unemployed, it takes older workers far longer than younger workers to find a new job, so a policy of not hiring the long-term unemployed has an age discriminatory effect," says Deborah Chalfie, AARP's senior legislative representative for financial security & consumer affairs.

Such policies are all too common in the current economy. And older workers can be frequent victims. As of June, jobless people who were 55 and older had been out of work for almost 56 weeks, compared with 38 weeks for all age groups, according to the Bureau of Labor Statistics.

Are you being discriminated against based on your current employment status? — Photo by Corbis

Unemployed need not apply

So just how common is the practice? Some employers suggest that it's rare. Mike Aitken, vice president of government affairs for the Society for Human Resource Management, says that, while there may be employers who follow that policy, his group is "unaware of this as a widespread practice."

He says that in a recent talk to an audience of more than 400 employers at the society's annual meeting, he asked whether any of the attendees had ever written such a job posting. "No one did," Aitken said. "The reaction was more like, 'What a dumb practice.'"

But an advocacy group that has looked into the issue comes to a different conclusion. In a review of help-wanted online postings between March 9 and April 5, 2011, the National Employment Law Project found 150 ads screening applicants based on current employment status.

Online job listing site CareerBuilder was among the sites accepting such ads. Although the company has issued a statement that it "strongly supports fair and equal hiring practices," critics ask why it hasn't simply refused to run the ads.

Next: 6 responses to use if you are being discriminated against. »