title: Rigor of research methods in studies of the effectiveness and safety of cataract extraction with intraocular lens implantation. Cataract Patient Outcome Research Team.
abstract: OBJECTIVE
  To assess the rigor of research methods reported in studies of the safety or effectiveness of contemporary cataract surgery.
  
  
  METHODS
  Formal systematic identification of pertinent studies and critical appraisal of each study's research methods.
  
  
  METHODS
  From 6113 unique, potentially relevant citations that we identified, 90 original studies published between 1979 and 1991 that addressed visual acuity or complications following standard extracapsular cataract extraction with posterior chamber intraocular lens implantation, phacoemulsification with posterior chamber intraocular lens implantation, or intracapsular cataract extraction with flexible anterior chamber intraocular lens implantation.
  
  
  METHODS
  Strength of study design, performance, and reporting in 11 methodologic areas assessed with a standardized abstraction form by two reviewers masked to authors, their institutions, and the journal of publication. Results of reviews were tallied to produce an overall quality score (measure of rigor in research methods) for each study.
  
  
  RESULTS
  The mean (+/- SD) quality score was 43.1 +/- 20.1 out of a maximum possible score of 100. Studies received intermediate scores on description of baseline ocular disease and low scores on descriptions of other characteristics of enrolled patients, standardization of outcome assessment and follow-up duration, and handling of patient attrition. Eighty-three studies (92%) lacked a comparison group. The rigor of research methods in studies varied by the journal of publication, did not improve over time, and was no greater for studies with larger vs smaller sample sizes.
  
  
  CONCLUSIONS
  The rigor of research methods in studies of cataract surgery can be improved if more attention is paid to fundamental principles of study design, data analysis, and reporting.
authors.affiliation: Johns Hopkins Program for Medical Technology and Practice Assessment, Johns Hopkins University School of Hygiene and Public Health, Baltimore, Md.
authors.forename: N R
authors.initials: NR
authors.lastname: Powe
authors.forename: J M
authors.initials: JM
authors.lastname: Tielsch
authors.forename: O D
authors.initials: OD
authors.lastname: Schein
authors.forename: R
authors.initials: R
authors.lastname: Luthra
authors.forename: E P
authors.initials: EP
authors.lastname: Steinberg
mesh_terms: D002387:Cataract Extraction / Q000009:adverse effects / Q000706:statistics & numerical data*; D015331:Cohort Studies; D003627:Data Interpretation, Statistical; D006801:Humans; D007910:Lenses, Intraocular; D016239:MEDLINE; D010043:Outcome and Process Assessment, Health Care / Q000706:statistics & numerical data; D012107:Research Design / Q000592:standards*; D014481:United States