The hiring of temporary workers has surged, suggesting that the nation’s employers might soon take the next step, bringing on permanent workers, if they can just convince themselves that the upturn in the economy will be sustained.

As demand rose after the last two recessions, in the early 1990s and in 2001, employers moved more quickly. They added temps for only two or three months before stepping up the hiring of permanent workers. Now temp hiring has risen for four months, the economy is growing, and still corporate managers have been reluctant to shift to hiring permanent workers, relying instead on temps and other casual labor easily shed if demand slows again.

“When a job comes open now, our members fill it with a temp, or they extend a part-timer’s hours, or they bring in a freelancer  and then they wait to see what will happen next,” said William J. Dennis Jr., director of research for the National Federation of Independent Business.

The rising employment of temp workers is not all bad. However uncertain their status, they do count in government statistics as wage-earning workers, adding to the employment rolls and helping to bring down the monthly job loss to just 11,000 in November. Indeed, the unemployment rate fell in 36 states in November, the Bureau of Labor Statistics reported last week, partly because of the growing use of temps.