Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
The probability that a signal is correct as a function of the outbreak occurrence rate, for different specificity (Sp) and sensitivity (Se). Black: Sp = 0.95, blue: Sp = 0.9, red: Sp = 0.8; straight line: Se = 0.99, long dash: Se = 0.9, short dash: Se = 0.5.
