title: ESSENCE II and the framework for evaluating syndromic surveillance systems.
abstract: BACKGROUND
  The Electronic Surveillance System for the Early Notification of Community-Based Epidemics (ESSENCE II) is a prototype syndromic surveillance system for capturing and analyzing public health indicators for early detection of disease outbreaks.
  
  
  OBJECTIVE
  This paper presents a preliminary evaluation of ESSENCE II according to a CDC framework for evaluating syndromic surveillance systems.
  
  
  METHODS
  Each major topic of the framework is addressed in this assessment of ESSENCE II performance.
  
  
  RESULTS
  ESSENCE captures data in multiple formats, parses text strings into syndrome groupings, and applies multiple temporal and spatio-temporal outbreak-detection algorithms. During a recent DARPA evaluation exercise, ESSENCE algorithms detected a set of health events with a median delay of 1 day after the earliest possible detection opportunity.
  
  
  CONCLUSIONS
  ESSENCE II has provided excellent performance with respect to the framework and has proven to be a useful and cost-effective approach for providing early detection of health events.
authors.affiliation: Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723, USA. Joe.Lombardo@jhuapl.edu
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Lombardo
authors.forename: H
authors.initials: H
authors.lastname: Burkom
authors.forename: J
authors.initials: J
authors.lastname: Pavlin
mesh_terms: D000465:Algorithms; D004196:Disease Outbreaks / Q000517:prevention & control*; D015991:Epidemiologic Measurements; D005069:Evaluation Studies as Topic; D006801:Humans; D011159:Population Surveillance / Q000379:methods*; D040442:Public Health Informatics / Q000295:instrumentation*