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.
The country needs to train 3,000 to 10,000 more physicians a year â up from the current 25,000 â to meet the growing medical needs of an aging, wealthy nation, the studies say. Because it takes 10 years to train a doctor, the nation will have a shortage of 85,000 to 200,000 doctors in 2020 unless action is taken soon.emographic changes in the medical profession also contribute to the need for more physicians. Nearly half of new physicians are women, and studies show they work an average of 25% fewer hours than male physicians, Cooper says. Physicians older than 55 work about 15% less than younger doctors.