If you use many independent contractors, you have reason to be nervous these days. The IRS and tax auditors in many states are aggressively assessing back payroll taxes on companies whose contractors they consider to be de facto employees.

There's comfort in The Employer's Guide to Using Independent Contractors, by Tim Stalnaker (BNA Books, Rockville, Md., 800-372-1033, 1993, $37), which details the 20 common-law guidelines the IRS uses to determine the status of workers; the guidelines applied by various states; and the tests used for specific industries. Stalnaker enumerates the many penalties for worker misclassification and suggests ways to avoid it, illustrating his advice with case histories.

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