The amount of money you can earn as a physical therapy assistant is almost entirely up to you. There are factors that play into the amount you can earn but, you also have control over that factor. Choose a specialty,  it helps. In most fields of science or medicine, choosing a specialty helps you earn more. As a physical therapy assistant, the area of specialty will have a great deal to do with your income. When it comes to being an assistant, there are seven common areas of specialty available for you to …