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.
From 1965 to 1992, the number of generalist physicians (defined as those in family or general practice, general internal medicine, or general pediatrics) increased by only 13 percent, to 7 per 100,000 population, whereas the number of specialist physicians increased 121 percent, to 124 per 100,000.