title: AMSTAR is a reliable and valid measurement tool to assess the methodological quality of systematic reviews.
abstract: OBJECTIVE
  Our purpose was to measure the agreement, reliability, construct validity, and feasibility of a measurement tool to assess systematic reviews (AMSTAR).
  
  
  METHODS
  We randomly selected 30 systematic reviews from a database. Each was assessed by two reviewers using: (1) the enhanced quality assessment questionnaire (Overview of Quality Assessment Questionnaire [OQAQ]); (2) Sacks' instrument; and (3) our newly developed measurement tool (AMSTAR). We report on reliability (interobserver kappas of the 11 AMSTAR items), intraclass correlation coefficients (ICCs) of the sum scores, construct validity (ICCs of the sum scores of AMSTAR compared with those of other instruments), and completion times.
  
  
  RESULTS
  The interrater agreement of the individual items of AMSTAR was substantial with a mean kappa of 0.70 (95% confidence interval [CI]: 0.57, 0.83) (range: 0.38-1.0). Kappas recorded for the other instruments were 0.63 (95% CI: 0.38, 0.78) for enhanced OQAQ and 0.40 (95% CI: 0.29, 0.50) for the Sacks' instrument. The ICC of the total score for AMSTAR was 0.84 (95% CI: 0.65, 0.92) compared with 0.91 (95% CI: 0.82, 0.96) for OQAQ and 0.86 (95% CI: 0.71, 0.94) for the Sacks' instrument. AMSTAR proved easy to apply, each review taking about 15 minutes to complete.
  
  
  CONCLUSIONS
  AMSTAR has good agreement, reliability, construct validity, and feasibility. These findings need confirmation by a broader range of assessors and a more diverse range of reviews.
authors.affiliation: Community Information and Epidemiological Technologies (CIET), Institute of Population Health, Ottawa, Ontario, Canada. bshea@ciet.org
authors.forename: Beverley J
authors.initials: BJ
authors.lastname: Shea
authors.forename: Candyce
authors.initials: C
authors.lastname: Hamel
authors.forename: George A
authors.initials: GA
authors.lastname: Wells
authors.forename: Lex M
authors.initials: LM
authors.lastname: Bouter
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Kristjansson
authors.forename: Jeremy
authors.initials: J
authors.lastname: Grimshaw
authors.forename: David A
authors.initials: DA
authors.lastname: Henry
authors.forename: Maarten
authors.initials: M
authors.lastname: Boers
mesh_terms: D019317:Evidence-Based Medicine / Q000379:methods / Q000592:standards*; D005240:Feasibility Studies; D006801:Humans; D015588:Observer Variation; D011786:Quality Control; D015203:Reproducibility of Results; D012107:Research Design / Q000592:standards; D012196:Review Literature as Topic