title: [Diversity and frequency of scientific research design and statistical methods in the "Arquivos Brasileiros de Oftalmologia": a systematic review of the "Arquivos Brasileiros de Oftalmologia"--1993-2002].
abstract: OBJECTIVE
  To verify the frequency of study design, applied statistical analysis and approval by institutional review offices (Ethics Committee) of articles published in the "Arquivos Brasileiros de Oftalmologia" during a 10-year interval, with later comparative and critical analysis by some of the main international journals in the field of Ophthalmology.
  
  
  METHODS
  Systematic review without metanalysis was performed. Scientific papers published in the "Arquivos Brasileiros de Oftalmologia" between January 1993 and December 2002 were reviewed by two independent reviewers and classified according to the applied study design, statistical analysis and approval by the institutional review offices. To categorize those variables, a descriptive statistical analysis was used.
  
  
  RESULTS
  After applying inclusion and exclusion criteria, 584 articles for evaluation of statistical analysis and, 725 articles for evaluation of study design were reviewed. Contingency table (23.10%) was the most frequently applied statistical method, followed by non-parametric tests (18.19%), Student's t test (12.65%), central tendency measures (10.60%) and analysis of variance (9.81%). Of 584 reviewed articles, 291 (49.82%) presented no statistical analysis. Observational case series (26.48%) was the most frequently used type of study design, followed by interventional case series (18.48%), observational case description (13.37%), non-random clinical study (8.96%) and experimental study (8.55%).
  
  
  CONCLUSIONS
  We found a higher frequency of observational clinical studies, lack of statistical analysis in almost half of the published papers. Increase in studies with approval by institutional review Ethics Committee was noted since it became mandatory in 1996.
authors.affiliation: Departamento de Oftalmologia da Irmandade, Santa Casa de Misericórdia de São Paulo, São Paulo, Brazil.
authors.forename: Fernando
authors.initials: F
authors.lastname: Crosta
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Nishiwaki-Dantas
authors.forename: Wilmar
authors.initials: W
authors.lastname: Silvino
authors.forename: Paulo Elias Correa
authors.initials: PE
authors.lastname: Dantas
mesh_terms: D015706:Bibliometrics; D001938:Brazil; D028744:Ethics Committees, Research; D006801:Humans; D009885:Ophthalmology / Q000706:statistics & numerical data*; D010506:Periodicals as Topic / Q000706:statistics & numerical data*; D012107:Research Design / Q000706:statistics & numerical data*; D013223:Statistics as Topic / Q000379:methods*