If you want to comply with state and federal regulations on classifying workers, talk to an HR expert. Rules vary from state to state.
Still, there are some basic guidelines suggested by the following experts: Andrew Schultz, president of Pro Unlimited Inc., the $110 million workforce management consultancy in Boca Raton, Fla.; Noreen McDermott, a lawyer with the firm of Baker & McKenzie, in Chicago; and Jeffrey Pasek, a partner at the law firm of Cozen and O'Connor.
Pay independent contractors by the project, not by the hour. Separate contractors from the mainstream workforce. Almost anything -- a contractor's presence on your softball team or at company meetings -- can be used to prove that the contractor is an employee.
Bar contractors from company resources. Truly independent contractors pay their own expenses, use their own equipment, and work on their own premises.
Screen all incoming workers. Use a lawyer-approved written test, asking questions about the contractors' independence.
Reassess the classifications of your workforce every six months. Regulations can change, as can your relationship with a worker.