It is very important that you classify workers properly. The mistake of classifying an employee as an independent contractor can be costly.
What is the definition of an Independent Contractor per the IRS?
20FactorTestforIndependentContractors
Here is an example of the type of form your company should have for Vendor On-boarding.
Example Independent Contractor Questionaire
And just for good measure, GO! is considered an Independent Contractor and here is our current W-9.