By full-time we also mean someone who is working for you for months and years. Independent business people sometimes look like employees. A business generally promises you a job done and then does it with its own equipment, often on its own premises, and in its own way. Your concern is just with the end product. This issue is often very fuzzy.
Independent businesses try to have more than a single customer.
Sometimes it comes down to the written contract you have with the person. The IRS considers this issue to be a problem in some specific industries. You can find this information in IRS audit training guides if one has been written for your business. It will tell you what the IRS would look for in your case.