Here is the design of a clinical trial:

Official Title: The Effectiveness of Managed Transition in Improving the Health and Social Outcomes for Young People Transitioning From Child to Adult Mental Health Care: the MILESTONE Study

Included conditions:
- Mental Health Impairment
- Mental Health Disorder

Study Armgroups:
- {'label': 'TRAM feedback', 'type': 'EXPERIMENTAL', 'description': '1. The completion of the "Transition Readiness and Appropriateness Measure" (TRAM, a standardized structured assessment ) prior to the transition boundary by the child and adolescent mental health service (CAMHS) clinician, young person and parent/carer.\n2. Feedback of TRAM findings to the CAMHS clinician to support decisions made regarding transition, communication with stakeholders and the transition process. Clinicians will be expected to communicate the findings to the young person and parent/carer, and, if a referral is made, to send the TRAM feedback to the adult clinician along with the referral letter.\n3. The clinicians will also receive information prior to recruitment begin on the use of TRAM and the way in which it fits in with optimal transition.', 'interventionNames': ['Behavioral: TRAM feedback']}
- {'label': 'Usual care', 'type': 'NO_INTERVENTION', 'description': "Patients, parent/carers and clinicians in the control arm will complete the TRAM prior to the transition boundary, but the clinicians won't receive any feedback from it nor any information on the benefits of using the decision support tool."}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'TRAM feedback', 'armGroupLabels': ['TRAM feedback'], 'otherNames': ['Managed transition']}

Primary Outcomes:
- {'measure': 'Mental health status (need for care) as measured by Health of the Nation Outcome Scale for Children and Adolescents (HoNOSCA - clinician version) at 15 months', 'description': 'The measure will be completed by a trained MILESTONE research assistant taking into account all available sources of information (including the young person, parent/carer, relevant clinician and the medical records) to ensure accuracy of data.', 'timeFrame': '15 months'}

Please estimate the sample size based on the assumption: 
Power calculations and significance levels are described in the protocol paper for the MILESTONE study.
Sample size
        For the preliminary validation of the scales, the total sample size across the eight countries was calculated to be approximately 100 participants in each group (i.e., 100 young people, 100 parents/carers/spouses, and 100 mental health professionals), which was based on sample size calculations.
        The power calculations linked with the external validation have been described in the protocol paper for the MILESTONE study [39]. For the analysis of external validity, all participants in the MILESTONE study (the cohort and control arms) participated, resulting in a group of approximately 3000 participants (1000 YP, 1000 PC and 1000 CL).