title: Identifying evidence for public health guidance: a comparison of citation searching with Web of Science and Google Scholar.
abstract: OBJECTIVE
  To examine how effectively forwards citation searching with Web of Science (WOS) or Google Scholar (GS) identified evidence to support public health guidance published by the National Institute for Health and Care Excellence.
  
  
  METHODS
  Forwards citation searching was performed using GS on a base set of 46 publications and replicated using WOS.
  
  
  RESULTS
  WOS and GS were compared in terms of recall; precision; number needed to read (NNR); administrative time and costs; and screening time and costs. Outcomes for all publications were compared with those for a subset of highly important publications.
  
  
  RESULTS
  The searches identified 43 relevant publications. The WOS process had 86.05% recall and 1.58% precision. The GS process had 90.7% recall and 1.62% precision. The NNR to identify one relevant publication was 63.3 with WOS and 61.72 with GS. There were nine highly important publications. WOS had 100% recall, 0.38% precision and NNR of 260.22. GS had 88.89% recall, 0.33% precision and NNR of 300.88. Administering the WOS results took 4 h and cost £88-£136, compared with 75 h and £1650-£2550 with GS.
  
  
  CONCLUSIONS
  WOS is recommended over GS, as citation searching was more effective, while the administrative and screening times and costs were lower.
authors.affiliation: National Institute for Health and Care Excellence, Guidance Information Services, Manchester, UK.
authors.forename: Paul
authors.identifier: http://orcid.org/0000-0003-1784-3314
authors.initials: P
authors.lastname: Levay
authors.affiliation: National Institute for Health and Care Excellence, Centre for Public Health, Manchester, UK.
authors.forename: Nicola
authors.initials: N
authors.lastname: Ainsworth
authors.affiliation: National Institute for Health and Care Excellence, Centre for Public Health, Manchester, UK.
authors.forename: Rachel
authors.initials: R
authors.lastname: Kettle
authors.affiliation: National Institute for Health and Care Excellence, Centre for Public Health, Manchester, UK.
authors.forename: Antony
authors.initials: A
authors.lastname: Morgan
mesh_terms: D015992:Body Mass Index; D003625:Data Collection; D016206:Databases, Bibliographic; D005006:Ethnicity; D019317:Evidence-Based Medicine; D006801:Humans; D016247:Information Storage and Retrieval / Q000379:methods*; D020407:Internet; D011634:Public Health / Q000379:methods* / Q000592:standards; D011642:Publications; D015203:Reproducibility of Results; D012196:Review Literature as Topic; D012586:Science; D055105:Waist Circumference
keywords: citation searching; google scholar; information retrieval; literature searching; public health guidance; web of science