The true test of being an independent contractor is the IRS 1099 form at the end of the year. Another way to tell is by the name of the company on your paycheck. Most temporary workers are paid by a temp agency, they are employees of the temp agency. The same is true for computer consultants who get their jobs through a computer manufacturer.
That being said, there are many court cases that are brought to answer the question, “Am I an employee?” This usually happens when a worker is in an auto accident or does something that injures another person. Then the employer/temp agency/consulting firm attempts to avoid any liability from the act of the worker.
Courts look at the control that the employer has on the worker to determine if he or she is an employee or an independent contractor. The more control the employer has over the worker in terms of what tasks to do, how to do them, when to do them, etc., the more the worker looks like an employee.