Abstract
The New York City (NYC) syndromic surveillance system has been monitoring syndromes from city emergency department (ED) visits for over a decade. We applied four aberration detection methodologies to a time series of ED visits in NYC spiked with synthetic outbreaks. Among the methods tested, performance varied by outbreak type and size; sudden large one-day spikes in cases were the most commonly detected, although sensitivity was low. The methods tested did not perform well; variability in method performance by outbreak type suggests multiple methods may be ideal for detecting different outbreak features.