Figure 1

Trends in emergency department visits seen by mid-level providers with or without direct physician involvement, 1993–2009. Physician assistant visits without physician involvement (solid circle): slope = 0.002 (95%CI, 0.001 to 0.003). Nurse practitioner visits without physician involvement (solid square): slope = 0.001 (95%CI, 0.0007 to 0.002). Physician assistant visits with physician involvement (empty circle): slope = 0.002 (95%CI, 0.0016 to 0.003). Nurse practitioner visits with physician involvement (empty square): slope = 0.001 (95%CI, 0.0009 to 0.002).