Calling someone a contractor does not make them one. Worker classification is decided by the nature of the relationship, not by the label on the agreement, and getting it wrong is one of the more expensive mistakes a small organization can make. Here is the plain version of how the line works.
Why it matters
Employees come with tax withholding, overtime rules, benefits eligibility, and protections that independent contractors do not have. When a worker is treated as a contractor but functions as an employee, the organization can owe back taxes, penalties, and more, sometimes reaching back years. The stakes are real, which is why agencies look closely.
What actually decides it
The core question is control. The more the organization controls how, when, and where the work gets done, the more the relationship looks like employment. A true contractor generally sets their own methods, uses their own tools, can work for others, and is paid for a result rather than for their time on your schedule.
Common ways it goes wrong
Problems usually come from drift rather than intent. A contractor is brought on for a project, then gradually becomes a fixture, attending the meetings, following the schedule, and using the equipment of an employee. The paperwork still says contractor, but the relationship has quietly become something else.
A practical safeguard
Use a proper agreement, have contractors submit a W-9, keep the relationship genuinely independent, and review long running engagements periodically to make sure the reality still matches the classification. When in doubt, the conservative reading protects you.
The label on the contract does not decide classification. The day to day reality of the relationship does.
Classification questions are easier to get right at the start than to fix after the fact. This article is general information, not legal or tax advice, so check specifics for your situation.