From a review of medical licensing:

By almost all accounts, the quality of services consumers get from non-physician clinicians is at least on par with what they would get from a physician performing the same services. Dozens of peer-reviewed studies compare outcomes in situations where patients are treated by a physician, a physician assistant, or an advanced practice nurse.  Outcomes appear similar [15] – an important factor, considering that non-physician clinicians can provide many services at a much lower cost. …

A review of more than 50 studies by the American Medical Association’s Council on Medical Education found that the peer reviewed studies "almost uniformly conclude that . . . a non-physician clinician. . . can provide an acceptable level of care."  The Council did note that some observers find serious flaws in the literature, including small samples, lack of control subjects, and failure to control for differences in the severity of illness treated by physicians and non-physician clinicians. Nevertheless, physician groups are unable to point to studies showing worse health outcomes with mid-level clinicians.

Again a deafening silence.  Dozens of studies over decades consistently find no patient health differences between expensive docs and cheaper clinicians, but there is zero momentum to let clinicians replace docs – policy trends go the other way.  The "establishment" complains about flaws in existing studies, but feels no need to do better studies.  What is the point of social science if even relatively clear important results are ignored? 

Don’t tell me this is just because the public hasn’t heard about these studies – the media  covers lots of med news they think the public wants to hear.  My local paper has a whole weekly health section.  Obviously the media doesn’t think the public wants to hear how they can drastically reduce med costs without sacrificing health.  Medicine is not about health. School is not about Learning.  FYI, here are some of those many studies: 

[15] Richard O. Nenstiel et al., "Allied Health and Physician Assistants: A Progressive Partnership," Journal of Allied Health 26 (1997): 133-35; Teresa M. O’Connor and Roderick S.Hooker, "Extending Rural and Remote Medicine with a New Type of Health Worker: Physician Assistants," Australian Journal of Rural Health 15 (2007): 346-51; Justine Strand,Nancy M. Short, and Elizabeth G. Korb, "The Roles and Supply of Nurse-Midwives, Nurse Practitioners, and Physician Assistants in North Carolina," North Carolina Medical Journal 68(2007):184-85; Peter J.Zed, Peter S. Loewen, and Peter J. Jewesson, "A Response to the ACP-ASIM Position Paper on Pharmacist Scope of Practice," American Journal of Health-System Pharmacy 59 (2002): 1453-57; Michael J. Dacey et al., "The Effect of Rapid Response Team on Major Clinical Outcome Measures in a Community Hospital," Critical Care Medicine 35 (2007): 2076-82; R. Tamara Konetzka, William Spector, and M. Rhona Limcangco, "Reducing Hospitalizations from Long-Term Care Settings," Medical Care Research and Review 2007. F. J. van den Biggelaar, P. J. Nelemans, and K. Flobbe, Performance of Radiographers in Mammogram Interpretation: A Systematic Review," Breast, 2007; James D. Woodburn, Kevin L. Smith, and Glen D. Nelson, "Quality of Care in the Retail Health Care Setting Using National Clinical Guidelines for Acute Pharyngitis," American Journal of Medical Quality 22 (2007): 457-62; Daisha J.Cipher,Roderick S.Hooker, and Patricia Guerra, "Prescribing Trends by Nurse Practitioners and Physician Assistants in the United States." Journal of the American Academy of Nurse Practitioners 18 (2006): 291-96; Morton Kern, "Letter from the Editor: The Scope of Practice in the Cath Lab: Are There Limits as to What Cath Lab Staff Should Do?" Cath Lab Digest 14 (2006): 6-8; Leah S. Sansbury et al., "Physicians’ Use of Nonphysician Healthcare Providers for Colorectal Cancer Screening," American Journal of PreventiveMedicine 25 (2003): 179-86; G. Wivell et al. "Can Radiographers Read Screening Mammograms?" Clinical Radiology 58 (2003): 63-67; Roderick S. Hooker and Linda F. McCaig, "Use of Physician Assistants and Nurse Practitioners in Primary Care, 1995-1999," Health Affairs 20 (2001): 231-38; Roderick.S. Hooker and Linda F. McCaig, "Emergency Department Uses of Physician Assistants and Nurse Practitioners: A National Survey," American Journal of Emergency Medicine 14 (1996): 245-49; Gary M. Karlowicz and Jennifer L. McMurray, "Comparison of Neonatal Nurse Practitioners’ and Pediatric Residents’ Care of Extremely Low-Birth-Weight Infants," Archives of Pediatrics & Adolescent Medicine 154 (2000): 1123-26. For additional citations, see Shirley Svorny, Physicians and Non-Physician Clinicians: Where Does Quality Assurance Come From?" in What Can States Do to Reform Healthcare, ed. John Graham (San Francisco:Pacific Research Institute,2006), pp.67-82.