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.
There are approximately 79,000 individuals eligible to practice as of January 2008 and 67,000 PAs currently practicing in the United States. In the late 1990âs a white paper developed by the Association of Physician Assistant Programs, recommended the move from undergraduate training to graduate level training.