Distribution of notification dates* of increased influenza activity relative to the UUPCRN epidemic onset by notification source^† for seasons 2004-05 through 2007-08. *Notification dates were based on the date that Sentinel Physician ILI reports were posted to the CDC and UDOH websites and the theoretical notification by email to UUPCRN clinicians 2 days following the early alert signal. ^†Notification source: CDC—Centers for Disease Control and Prevention. The national ILI threshold ranged from 2.1% to 2.5% during the study years. UDOH—Utah Department of Health. The historical Utah-specific ILI threshold was 3.6% during the study years and is shown as the first UDOH group in the graph. The threshold was recalculated in 2008-09 to 1.7% and is shown as the second UDOH group. The 1.7% threshold demonstrates the shift in notification date if this threshold had been used in the study years. UUPCRN—University of Utah Primary Care Research Network. The notification date is based on a theoretical email notification sent to clinicians 2 days after the modeled real-time surveillance alert.