Selection Bias Selection bias occurs when the selection of participants in one group results in a different outcome than the selection for the other group
1 As of 2015, there are more than 96,000 osteopathic medical physicians in the United States.  By 2020, the number of osteopathic medical physicians will be over 100,000, say expert predictions, according to the American Medical Association.
Today there are more than 77,000 licensed Doctors of Chiropractic (DC) in the U.S. alone, plus thousands more practicing in countries throughout the world. (1) As one of the most popular types of alternative treatment approaches (meaning those that are non-medical), millions of people each year seek chiropractic care.