B.C.B.A or B.C.a.B.A Behavior Analyst are individuals who have complete specialized course work in the field of Behavior Analysis, including Applied Behavior Analysis from an accredited university. They have then completed the corresponding supervision requirements and passed the national credentialing exam.
There are currently three levels of certification from the Behavior Analyst Certification Board.

B.C.B.A-D - Board Certified Behavior Analyst-Doctorate Level
B.C.B.A - Board Certified Behavior Analyst-Master’s Level  
B.C.a.B.A - Board Certified associate Behavior Analyst-Bachelor’s Level