title: Success Factors of European Syndromic Surveillance Systems: A Worked Example of Applying Qualitative Comparative Analysis.
abstract: Syndromic surveillance aims at augmenting traditional public health surveillance with timely information. To gain a head start, it mainly analyses existing data such as from web searches or patient records. Despite the setup of many syndromic surveillance systems, there is still much doubt about the benefit of the approach. There are diverse interactions between performance indicators such as timeliness and various system characteristics. This makes the performance assessment of syndromic surveillance systems a complex endeavour. We assessed if the comparison of several syndromic surveillance systems through Qualitative Comparative Analysis helps to evaluate performance and identify key success factors.
  
  
  
  We compiled case-based, mixed data on performance and characteristics of 19 syndromic surveillance systems in Europe from scientific and grey literature and from site visits. We identified success factors by applying crisp-set Qualitative Comparative Analysis. We focused on two main areas of syndromic surveillance application: seasonal influenza surveillance and situational awareness during different types of potentially health threatening events.
  
  
  
  We found that syndromic surveillance systems might detect the onset or peak of seasonal influenza earlier if they analyse non-clinical data sources. Timely situational awareness during different types of events is supported by an automated syndromic surveillance system capable of analysing multiple syndromes. To our surprise, the analysis of multiple data sources was no key success factor for situational awareness.
  
  
  
  We suggest to consider these key success factors when designing or further developing syndromic surveillance systems. Qualitative Comparative Analysis helped interpreting complex, mixed data on small-N cases and resulted in concrete and practically relevant findings.
authors.affiliation: Department of International Health, CAPHRI School of Public Health and Primary Care, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Ziemann
authors.affiliation: Institute de Veille Sanitaire, Saint Maurice cedex, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Fouillet
authors.affiliation: Department of International Health, CAPHRI School of Public Health and Primary Care, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.
authors.forename: Helmut
authors.initials: H
authors.lastname: Brand
authors.affiliation: Department of Health, Ethics and Society, CAPHRI School of Public Health and Primary Care, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.
authors.forename: Thomas
authors.initials: T
authors.lastname: Krafft
mesh_terms: D005060:Europe / Q000453:epidemiology; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology; D062486:Public Health Surveillance; D036301:Qualitative Research; D013577:Syndrome