Abstract
Electronic event-based biosurveillance systems (EEBS''s) are an increasingly important source of epidemiologic intelligence. We assessed 17 published evaluations on 10 EEBS''s using 17 key variables from CDC guidelines for surveillance system evaluations. The median number of key variables assessed per EEBS was 6 (range, 3-12). Very few evaluations were quantitative, and no evaluations examined system usefulness by identifying specific public health decisions, actions, or outcomes resulting from early event detection. Future EEBS evaluations should quantitatively examine these critical indicators of utility, assess novel aspects of EEBS''s, and consider the effects of combining EEBS''s into super systems.