title: An encouraging assessment of methods to inform priorities for updating systematic reviews.
abstract: OBJECTIVE
  To consider the use of statistical methods that aim to prioritize the updating of a collection of systematic reviews based on preliminary literature searches.
  
  
  METHODS
  A new simulation-based method estimating statistical power and the ratio of the weights assigned to the predicted new and old evidence, and the existing Barrowman n approach is considered. Using only information on the numbers of subjects randomized in the "new" trials, these were applied retrospectively, by removing recent studies, to existing systematic reviews from the Cochrane Infectious Diseases Group.
  
  
  RESULTS
  Twelve systematic reviews were included. When the removed studies were reinstated, inferences changed in five of them. These reviews were ranked, in order of update priority, 1, 2, 3, 4, and 11 and 1, 2, 3, 4, and 12 by the Barrowman n and simulation-based power approaches, respectively. The low ranking of one significant meta-analysis by both methods was due to unexpectedly favorable results in the reinstated study.
  
  
  CONCLUSIONS
  This study demonstrates the feasibility of the use of analytical methods to inform update prioritization strategies. Under conditions of homogeneity, Barrowman's n and simulated power were in close agreement. We encourage further, prospective, evaluation of these methods.
authors.affiliation: Department of Health Sciences, University of Leicester, Leicester, UK. ajs22@le.ac.uk
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Sutton
authors.forename: Sarah
authors.initials: S
authors.lastname: Donegan
authors.forename: Yemisi
authors.initials: Y
authors.lastname: Takwoingi
authors.forename: Paul
authors.initials: P
authors.lastname: Garner
authors.forename: Carol
authors.initials: C
authors.lastname: Gamble
authors.forename: Alison
authors.initials: A
authors.lastname: Donald
mesh_terms: D005240:Feasibility Studies; D006801:Humans; D016247:Information Storage and Retrieval / Q000592:standards*; D015201:Meta-Analysis as Topic; D015233:Models, Statistical; D016032:Randomized Controlled Trials as Topic; D012106:Research; D012196:Review Literature as Topic; D013997:Time Factors