Systematic Reviews
In 2003, Astin compiled results of 28 systematic reviews that included about 9,700 participants. He concluded that 71% of the research studies conducted on mind-body therapies had minor flaws, a much lower percentage that what is usually reported for conventional treatments.
Reference
Astin JA, Shapiro SL, Eisenberg DM, Forys KL. Mind-body medicine: State of the science, implications for practice. J Am Board Fam Pract 2003;16:131-47.