Although your query is a bit dated now-perhaps you are still wondering what to use. All of your concerns are addressed in a measure called the Y-OQ-2.01 or "Youth Outcome Questionnaire-Version 2.01" It was designed for repeated measurement, is low cost (one time nominal licensing fee), has high validity and reliability. This measure is being adopted by many large MBHO (Aetna, Deseret Mutual, CMG Health, Merit and more). There is strong ongoing research support particularly at Brigham Young Unversity. More information can be had by calling Diana Maslauskas, DCSW at 1-500-488-2727. I would also be happy to try to answer any questions you might have. I can be reached at apcs@erols.com.