Screening or human capital?

An article in the Lafayette Journal and Courier says that some employers do not want to hire people who have been unemployed for more than a year.

There is a stigma that long-term jobless people have been sitting around and don't really want to work. There is the perception that they won't take a lower-paying job -- and if they do, they will bolt as soon as they find a higher-paying one.
On top of that, some companies have explicitly barred the unemployed from certain job openings, outright telling them in job ads that they need not apply.

 ....
But the company is far from alone in wanting workers who already are gainfully employed, said Patrice Waidner, board chairwoman of the Indianapolis chapter of Business & Professional Exchange, a networking organization that helps unemployed professionals."Companies are saying, 'I will take the person who was just working or is currently working,' " she said. "It is extremely difficult to get back into the job market."

Does a person lose job skills as a result of being unemployed for a long time? Or does long-term unemployment tend to be a marker for people who are less reliable and dependable than average? The article does not tell us much, but then the reporter probably does recognize that these are interesting questions.