No single "treatment package" will serve every child's needs and no individual can claim to own ABA. ABA, for the treatment of autism, is the application of the principles of learning to 1) build skills and 2) treat problem behavior. It works because each person's behavior is assessed to determine what skills they have not mastered and what types of problem behavior interfere with learning and social functioning. For skill deficits, direct instruction is provided until the skill is mastered. For problem behavior, specific analysis of why the behavior occurs is used to develop treatment to eliminate the behavior or teach the person to use other more appropriate behavior to serve the same function.