That depends. If you work in someone else's home according to their schedule and their work rules, you are usually considered their household employee. They are required to pay wages, to withhold social security and medicare tax, and issue a W-2 at the end of the year. If you work out of your own home, or you work for several families in their homes, but you are able to set your own work conditions (like time off for appointments and vacations) then you are probably self-employed.
It's all about independence and control, who has more control over how, when and where you preform your work. This PDF may help.
https://www.irs.gov/pub/irs-pdf/p1779.pdf
