title: A review of evidence for the claim that children are sleeping less than in the past.
abstract: OBJECTIVE
  The notion that children are sleeping less than they used to is widespread. This study examined the strength of the evidence for this idea by tracing a "scholarly genealogy" of the claims presented within the literature.
  
  
  METHODS
  A systematic review of peer-reviewed literature was conducted to identify claims of a secular trend in children's sleep. For each identified claim, the references cited were reviewed.
  
  
  RESULTS
  The review identified 51 studies. Of these, 17 evinced evidence (2 reported increases, 3 reported no change, 6 reported mixed trends, 6 reported decreases) and 34 provided statements without evidence. Although the evidence that sleep duration has declined is contested, all 34 studies reported a decline. Examination of the references cited revealed that 17 papers referred directly to studies which provided evidence, 4 papers referred indirectly to studies which provided evidence, 9 papers did not provide any evidence and 4 papers referred to studies which could not be located. Of the papers that did provide evidence, 85% referred to one of 3 sources of evidence, each of which was of moderate quality.
  
  
  CONCLUSIONS
  The genealogy of the notion of secular declines in children's sleep reveals a limited scientific basis. The apparent evidence base is inflated by repeated references to the same sources of evidence, reference to secondary sources, mis-referencing, and a failure to cite contrary evidence.
authors.affiliation: Health and Use of Time Group, University of South Australia, Australia. matla005@students.unisa.edu.au
authors.forename: Lisa
authors.initials: L
authors.lastname: Matricciani
authors.forename: Tim
authors.initials: T
authors.lastname: Olds
authors.forename: Marie
authors.initials: M
authors.lastname: Williams
mesh_terms: D002648:Child; D006801:Humans; D002666:Psychology, Child; D012890:Sleep; D013997:Time Factors