Professional Research Services (PRS), a third-party research company, contacted each licensed and active chiropractor within the State of Missouri. Each chiropractor was asked to recommend up to three colleagues, other than themselves, in a given chiropractic specialty. Once the ballots were complete, each nominee was carefully evaluated on the basis of the survey results, the legitimacy of their license, and their current standing with the State Board of Chiropractic Examiners. Chiropractors who received the highest number of votes are reflected in this list. A listing in Top Chiropractors cannot be purchased, and advertising in the issue has no impact on whether or not a chiropractor is listed.