I did include the link to the HealthAffairs Health Policy Brief from which I took the quote....
Here are some more articles to whet your appetite:
Hatem, M., Sandall, J., Devane, D., et al. “Midwife-led Versus Other Models of Care for Childbearing Women,” Cochrane Database of Systematic Reviews, October 2008, Issue 4. Available at: http://apps.who.int/rhl/reviews/CD004667.pdf
Horrocks, S., Anderson, E., and Salisbury, C. “Systematic Review of Whether Nurse Practitioners Working in Primary Care Can Provide Equivalent Care to Doctors,” BMJ, April 6, 2002, Vol. 324, No. 7341, pp. 819-23.
Jackson, D.J., Lang, J.M., Swartz, W.H., et al. “Outcomes, Safety, and Resource Utilization in a Collaborative Care Birth Center Program Compared with Traditional Physician-Based Perinatal Care,” American Journal of Public Health, June 2003, Vol. 93, No. 6, pp. 999-1006.
Laurant, M.G., Hermens, R.P., Braspenning, J.C., et al. “An Overview of Patients’ Preference for, and Satisfaction with, Care Provided by General Practitioners and Nurse Practitioners,” Journal of Clinical Nursing, October 2008, Vol. 17, Issue 20, pp. 2690-698.
Lenz, E.R., Mundinger, M.O., Kane, R.L., et al. “Primary Care Outcomes in Patients Treated by Nurse Practitioners or Physicians: Two-Year Follow-Up,” Medical Care Research and Review, September 2004, Vol. 61, No. 3, pp. 332-51.
MacDorman, M.F. and Singh, G.K. “Midwifery Care, Social and Medical Risk Factors, and Birth Outcomes in the USA,” Journal of Epidemiology and Community Health, May 1998, Vol. 52, No. 5, pp. 310-17.
Mundinger, M.O., Kane, R.L., Lenz, E.R., et al. “Primary Care Outcomes in Patients Treated by Nurse Practitioners or Physicians,” Journal of the American Medical Association, January 5, 2000, Vol. 283, No. 1, pp. 59-68.
Naylor, M.D. and Kurtzman, E.T. “The Role of Nurse Practitioners in Reinventing Primary Care,” Health Affairs, May 2010, Vol. 29, No. 5, pp. 893-99.
Needleman, J. and Minnick, A.F. “Anesthesia Provider Model, Hospital Resources, and Maternal Outcomes,” Health Services Research, April 2009, Vol. 44, No. 2, pp. 464-82.
Pine, M., Holt, K.D., and Lou, Y. “Surgical mortality and Type of Anesthesia Provider,” American Association of Nurse Anesthetists Journal, Vol. 71, No. 2, pp. 109-16.
Silber, J.H. “Anesthesiologist Direction and Patient Oucomes,” Leonard Davis Institute of Health Economics Issue Brief, October 2000, Vol. 6, No. 2.
Wilson, I.B., Landon, B.E., Hirschhorn, L.R., et al. “Quality of HIV Care Provided by Nurse Practitioners, Physician Assistants, and Physicians,” Annals of Internal Medicine, November 15, 2005, Vol. 143, No. 10, pp. 729-36.