Randomized Clinical Trials (RCT) Provide Much Needed Outcomes Evidence for Art

Randomized clinical trials (RCT) provide much needed outcomes evidence for art therapy but they have their limitations. To be generalizable to actual practice, what two conditions are necessary?

A) The participants and settings must be representative of where art therapy programs are found, and the outcomes must be clinically relevant.
B) The primary investigator must be an art therapist and the outcomes must be beneficial to the average art therapy client.
C) The outcome measures taken must be statistically relevant and the treatment protocol must be systematically applied over a sufficient period of time.
D) There must be a large enough number of participants to create two perfectly matched groups and the treatment protocol must meet the needs of a variety of clients in the setting.