This study is designed to determine the use, cost, and effectiveness of chiropractic care in a community-based sample of persons representative of the non-elderly US population. Previous studies examining these questions either do not exist or have been regional or have suffered from design flaws and/or inadequate response rates such that generalizing their results to the US population may not be valid. This study will use data from the RAND Health Insurance Experiment (HIE), which was a large, social experiment designed to assess how cost-sharing affected patients' use of health services, their satisfaction with health care, the quality of their care, and the state of their health. This is the best community-based database containing this information on chiropractic care. This analysis will consist of four parts: 1) descriptive data on the use of chiropractic services, by whom, for what symptoms, what services are provided, and the like; 2) calculation of the demand elasticity of chiropractic care, and its cross-elasticity with outpatient medical care; 3) comparison of chiropractic care and allopathic care for patients with back pain for health service utilization, based on episodes of care; 4) comparison of chiropractic care and allopathic care for patients with back pain for effect on health status and satisfaction. The calculations of price elasticity will use a two-step model, as in previous calculations for medical care in the HIE. An episode of care is defined as a series of temporally contiguous health care services related to treatment of back pain, and will be constructed using rules linking visits and ancillary services. Each episode will then have associated utilization values for visits and charges. Multiple regression will be used to determine the effect of provider type on utilization. Multiple regression will also be used to determine the effect of provider choice on health status and satisfaction with health care. The results of this study can be expected to substantially improve our knowledge of the role chiropractors should have in the US health care system.
