We understand Dr. Hill's confusion over the criteria used in our study; space limitations prevented us from presenting the ratings for the full 1550 indications, along with their accompanying definitions (available from RAND [1]). The chronic low back pain indication rated as "appropriate" for spinal manipulation (with previous manipulation and favorable response—indication 45, chapter 9 of the RAND report) was also rated as appropriate with the identical clinical descriptors in the absence of any history of manipulation (indication 45, chapter 8). Ergo, a favorable response to manipulation was not necessary for an actual patient's care to be judged as appropriate. For subacute low back pain, several clinical presentations were rated as appropriate, both without previous manipulation and with current manipulation and a favorable response. In the judgment of our experts, continued manipulation was more likely to be appropriate if current manipulation was producing a favorable response than if current manipulation was producing no response. We would also like to remind Dr. Hill that the criteria were developed, not by us or the "medical profession," but by a group of medical and chiropractic specialists informed by the best available review of the scientific literature.

Drs. LaBan and Taylor's letter deals more with a critique of the methods used by the AHCPR Low Back Problems Clinical Guideline Panel than it does of our study. However, we believe readers should know that the conclusions LaBan and Taylor have reached about the effectiveness of spinal manipulation are either not supported or directly contradicted by good-quality randomized clinical trials (2-4).

Dr. Sportelli states that the results of our study might look very different were it repeated today, in the model of chiropractic care that is "managed, prospective, and measurable." We agree, but given the absence of data to support this assertion, we believe that a study should be performed to test this hypothesis. In contrast to Dr. Sportelli's concern that the message to the general public may be negative, our monitoring of the reports in the lay media about our study shows that these were generally positive. Finally, no data in our study allow us, or Dr. Sportelli, to conclude anything about the confidence the public should have in chiropractors relative to the confidence they have in any other provider who treats patients with low back pain. We do believe that the chiropractic profession should do everything possible to both eliminate inappropriate spinal manipulation and to make sure that people who would benefit from manipulation are offered the procedure.