An interesting study came out of the USA a few years ago. They looked to rate the effectiveness of chiropractic care against physical therapy and physician care. They found that chiropractic was the most effective health modality to reduce disability. Cifuentes M, Willetts J, Wasiak R; Health maintenance care in work-related low back pain and its association with disability recurrence (2011) J Occup Environ Med Apr;53(4):396-404 The abstract can be found here: http://www.ncbi.nlm.nih.gov/pubmed/21407100