title: Surveillance search techniques identified the need to update systematic reviews.
abstract: OBJECTIVE
  This article reports on literature surveillance methods to identify new evidence eligible for updating systematic reviews.
  
  
  METHODS
  Five surveillance search approaches are tested in the context of identifying studies that would signal major or invalidating new evidence for existing systematic reviews of health care interventions. Recall for each search approach was assessed as proportion of a composite yield of relevant studies across all search approaches that were identified by that approach. Screening burden was the number of studies that would need to be reviewed to identify the evidence that would necessitate updating.
  
  
  RESULTS
  Searches were tested in a cohort of 77 systematic reviews. No one method yielded consistently high recall of relevant new evidence, so combinations of the strategies were examined. A search algorithm based on PubMed's related article search in combination with a subject searching using clinical queries was the most effective combination, retrieving all relevant new records in 68 cases. Screening burden was a median of 71 new records per review (inter-quartile range: 42-161).
  
  
  CONCLUSIONS
  Surveillance for emerging evidence that signals the need to update systematic reviews is feasible using a combination of subject searching and searching based on the PubMed's related article function.
authors.affiliation: Chalmers Research Group, Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Road, Ottawa, Ontario K1H 8L1, Canada. msampson@cheo.on.ca
authors.forename: Margaret
authors.initials: M
authors.lastname: Sampson
authors.forename: Kaveh G
authors.initials: KG
authors.lastname: Shojania
authors.forename: Jessie
authors.initials: J
authors.lastname: McGowan
authors.forename: Raymond
authors.initials: R
authors.lastname: Daniel
authors.forename: Tamara
authors.initials: T
authors.lastname: Rader
authors.forename: Alla E
authors.initials: AE
authors.lastname: Iansavichene
authors.forename: Jun
authors.initials: J
authors.lastname: Ji
authors.forename: Mohammed T
authors.initials: MT
authors.lastname: Ansari
authors.forename: David
authors.initials: D
authors.lastname: Moher
mesh_terms: D000465:Algorithms; D015331:Cohort Studies; D003695:Delivery of Health Care; D005240:Feasibility Studies; D006801:Humans; D016247:Information Storage and Retrieval / Q000592:standards*; D016239:MEDLINE; D015201:Meta-Analysis as Topic; D039781:PubMed; D016032:Randomized Controlled Trials as Topic; D012196:Review Literature as Topic