Obsolescence of the literature: a study of included studies in Cochrane reviews

Tove Faber Frandsen*, Mette Brandt Eriksen, David Mortan Grøne Hammer


Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

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Aging or obsolescence describes the process of declining use of a particular publication over time and can affect the results of a citation analyses as the length of citation window can change rankings. Obsolescence may not only vary across fields but also across subfields or sub-disciplines. The aim of the present study is to determine the sub-disciplinary differences of obsolescence on a larger scale allowing for differences over time as well. The study presents the results of an analysis of 82,759 references across 53 health care and health policy topics. The references in this study are extracted from systematic reviews published from 2012 to 2016. The analyses of obsolescence include median citation age and mean citation age. This study finds that the median citation age as well as the mean citation age differ considerably across groups. For the latter indicator an analysis of the confidence intervals confirms these differences. Using the subfield categorization from Cochrane review groups we larger differences across subfields than in the citing half-lives published by Journal Citation Report. Obsolescence is important to consider when setting the length of the citation windows. This study emphasizes the vast differences across health sciences subfields. The length of the citation period is thus highly important for the results of a bibliometric evaluation or study covering fields with very varying obsolescence rates.
TidsskriftJournal of Information Science
Udgave nummer2
Sider (fra-til)437-447
StatusUdgivet - apr. 2023


  • Aging
  • Obsolescence
  • Diasynchronous
  • Mean citation age
  • Median citation age
  • Health sciences


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