title: Quality and transparency of overviews of systematic reviews.
abstract: OBJECTIVE
  To evaluate the reporting and methodological quality of overviews of systematic reviews.
  
  
  METHODS
  We developed an 18-item assessment tool for overviews of systematic reviews. We then performed a systematic search for such overviews using the terms ('overview' AND ('meta analys*' OR 'systematic review*')) OR 'umbrella review' in the title. We only included those overviews that were limited to systematic reviews or meta-analyses. Their methodological and reporting quality were assessed by two independent reviewers using the checklist, and differences were resolved by a third reviewer. Data analyses was conducted by SPSS version 15.0 for Windows.
  
  
  RESULTS
  We identified 41 overviews of systematic reviews whose mean total reporting score was 10.78 (SD 3.84) and methodological score 3.05 (SD 2.09). Some important items were not adequately reported: only 69% reported defined eligibility criteria, 76% reported search strategy, 49% reported the process of review selection, 44% reported the data collection process, 5% reported evaluating the reporting quality, 46% reported evaluating methodological quality, and 20% reported assessing the evidence level for each outcome.
  
  
  CONCLUSIONS
  The reporting and methodological quality of overviews of systematic reviews was very poor, and there is still much room for improvement. A checklist for overviews of systematic reviews should be developed and used.
authors.affiliation: Evidence-Based Medicine Center, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China The First Clinical College of Lanzhou University, Lanzhou, China.
authors.forename: Lun
authors.initials: L
authors.lastname: Li
authors.forename: Jinhui
authors.initials: J
authors.lastname: Tian
authors.forename: Hongliang
authors.initials: H
authors.lastname: Tian
authors.forename: Rao
authors.initials: R
authors.lastname: Sun
authors.forename: Yali
authors.initials: Y
authors.lastname: Liu
authors.forename: Kehu
authors.initials: K
authors.lastname: Yang
mesh_terms: D019317:Evidence-Based Medicine; D011787:Quality of Health Care