The length of time staffing buyers take to pay staffing firms is increasing, according to the Capital TempFunds credit index.

The index slipped to 98 in the fourth quarter of 2007 from 102 in the third and 104 in the second. The higher the number, the faster clients are paying.

For the month of January, the index was at 96, unchanged from December.

James Rothman, president of Capital TempFunds, said data for the index comes from its clients across the country. With the index, staffing firms can track how their customer base is paying compared with hundreds of other staffing companies.

"Payment history and payment cycles are so important to the staffing industry," Rothman said. "As payments tend to slow, the need for capital tends to increase."