Skilled Nursing Inc., a temporary-staffing service, matches 170 Philadelphia-area nurses with hospitals that need extra help for intensive-care wards. These nurses earn from $12 to $20 an hour, compared with an average of $8.75 to $17 for intensive-care nurses employed by other agencies, a spokesman says.

Skilled Nursing can offer more than the prevailing wage rates because it doesn't have a payroll and because the nurses who work for it aren't its employees. Instead, the nurses act as individual contractors, receiving fees for their services. The company saves money by paying no unemployment or Social Security taxes, providing no group health insurance, and avoiding the accounting headaches of payroll deductions. The nurses are responsible for paying their own income and Social Security taxes.

While some workers and employers may prefer this system, such arrangements rile the Internal Revenue Service because they make it much harder for Uncle Sam to collect. For more than a decade the IRS has been trying to tighten the definition of independent contractors. But protests by affected business groups, such as real estate agents, prompted a series of lawsuits and congressional disputes. In 1978 Congress passed a measure temporarily halting further IRS actions in this area.

Now Sen. Robert Dole (R-Kans.), chairman of the Finance Committee, proposes to resolve the impasse. Under his bill, S.2369, a worket is considered an independent contractor if the individual controls the number of hours worked and the schedule, provides a place of business, invests a substantial sum in the business or experiences fluctuation in income because of it, and has a contract stating the tax responsibilities of each party. Nine of the 20 Finance Committee members have signed on as co-sponsors of the bill, giving it a good chance to clear Congress.

Martha Minniti, president and founder of Skilled Nursing, won't be worried if the bill goes through. She says her company will pass the test. Some of her nurses have incorporated for the tax benefits, and their corporations will count as "places of business," she predicts.