The classification of independent contractor status is a major issue for small businesses. Robert W. Woods wrote a piece about this and it can be access with the link provided below. He also has additional links at the end of the article that can be very useful. One that I think is particularly important is the article entitled "10 Mistakes to Avoid On Independent Contractors". If you are audited by the IRS or EDD and have misclassified people it can get very expensive with the penalties that are charged.
IRS Narrows Independent Contractor Relief - Forbes