U.S. employers have more job openings than at any other time in nearly five years, according to government data released Tuesday. Yet, companies seem in no hurry to fill the openings.

That disparity helps explain why the job market remains tight and unemployment high. Even as openings have surged 11 percent in the past year, the number of people hired has declined.

Why so many openings yet so few hires? Economists point to several factors. Some unemployed workers lack the skills employers want. Some companies may not be offering enough pay. And staffing firms say that in a still-fragile economy many businesses seem hesitant to commit to new hires.

They appear to be holding out for the perfect candidate.

"We're living in a fear-based environment right now," says Kim First, CEO of the Agency Worldwide, a recruiting firm for pharmaceutical and biotech companies.

Those who do have jobs these days are unlikely to lose them. Layoffs have sunk to a pre-recession level.

But First says that companies feel they can't afford to take a risk by hiring someone who doesn't appear to be an ideal fit for the job they've advertised.

advertisement | advertise on newsday

"They are really reluctant to make that leap of faith," she says. Companies "need someone to come in and hit the ground running."

The Labor Department said Tuesday the number of job openings rose 8.7 percent in February from January to a seasonally adjusted 3.93 million. That was the most since May 2008.

At the same time, companies hired a seasonally adjusted 4.4 million people, just 2.8 percent more than in January. And hiring remained lower than it was a year ago, when it reached 4.49 million.

The figures suggest the Great Recession may have transformed the job market in ways that economists still don't fully understand. Normally, more openings lead, over time, to stronger hiring and steadily lower unemployment. Yet, in May 2008, when job openings were as numerous as they are now, the unemployment rate was 5.4 percent. Now it's 7.6 percent -- far above the 5 percent to 6 percent range associated with a healthy economy.

In 2007, before the recession, employers hired an average of 5.2 million people a month -- 15 percent more than in February this year.

The number of people quitting is low compared with pre-recession levels, though it's risen in recent months. A low number reduces opportunities for those out of work.

Some economists doubt a skills mismatch is playing a significant role in slow hiring and suspect a broad slowdown in the economy is to blame for still-high unemployment, rather than a shortage of qualified workers in certain industries.