In addition to the therapy, the qualifications of the agency and therapist, the method of measurement, etcc... It is important to not that therapy and skill acquisition will only be as good as how well it is generalized.  Generalization of the skill is essential for a skill to be utilized in real life.  For this to happen, therapy needs to include generalization of the skills and should also include parent training to teach the parent to generalize the skill.  There are many methods of teaching that can enhance ABA and generalization of skills.  I encourage parents to press the issue of skill generalization.  
mb palo www.watchmelearn.com