An occupational therapy assistant, or OTA, must have an associate degree and must be licensed in some states. OTA education includes courses in psychology, pediatric health, biology and anatomy. Clinical field work is the part of the OTA’s education that helps her gain hands-on clinical skills and work experience.An OTA must graduate from an accredited program in order to be licensed and may also take an examination to become a certified occupational therapy assistant.n addition to education and job task differences, salaries for the two roles are different. In 2011, the salary was $52,150 for an occupational therapy assistant and $74,970 for an OT, according to the Bureau of Labor Statistics.