title: Effect of blinded peer review on abstract acceptance.
abstract: BACKGROUND
  Peer review should evaluate the merit and quality of abstracts but may be biased by geographic location or institutional prestige. The effectiveness of blinded peer review at reducing bias is unknown.
  
  
  OBJECTIVE
  To evaluate the effect of blinded review on the association between abstract characteristics and likelihood of abstract acceptance at a national research meeting.
  
  
  METHODS
  All abstracts submitted to the American Heart Association's annual Scientific Sessions research meeting from 2000-2004. Abstract review included the author's name and institution (open review) from 2000-2001, and this information was concealed (blinded review) from 2002-2004. Abstracts were categorized by country, primary language, institution prestige, author sex, and government and industry status.
  
  
  METHODS
  Likelihood of abstract acceptance during open and blinded review, by abstract characteristics.
  
  
  RESULTS
  The mean number of abstracts submitted each year for evaluation was 13,455 and 28.5% were accepted. During open review, 40.8% of US and 22.6% of non-US abstracts were accepted (relative risk [RR], 1.81; 95% confidence interval [CI], 1.75-1.88), whereas during blinded review, 33.4% of US and 23.7% of non-US abstracts were accepted (RR, 1.41; 95% CI, 1.37-1.45; P<.001 for comparison between peer review periods). Among non-US abstracts, during open review, 31.1% from English- speaking countries and 20.9% from non-English-speaking countries were accepted (RR, 1.49; 95% CI, 1.39-1.59), whereas during blinded review, 28.8% and 22.8% of abstracts were accepted, respectively (RR, 1.26; 95% CI, 1.19-1.34; P<.001). Among abstracts from US academic institutions, during open review, 51.3% from highly prestigious and 32.6% from nonprestigious institutions were accepted (RR, 1.57; 95% CI, 1.48-1.67), whereas during blinded review, 38.8% and 29.0% of abstracts were accepted, respectively (RR, 1.34; 95% CI, 1.26-1.41; P<.001).
  
  
  CONCLUSIONS
  This study provides evidence of bias in the open review of abstracts, favoring authors from the United States, English-speaking countries outside the United States, and prestigious academic institutions. Moreover, blinded review at least partially reduced reviewer bias.
authors.affiliation: Robert Wood Johnson Clinical Scholars Program, Department of Internal Medicine, Yale University School of Medicine and Yale-New Haven Hospital Center for Outcomes Research and Evaluation, New Haven, Conn 06520-8088, USA.
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Ross
authors.forename: Cary P
authors.initials: CP
authors.lastname: Gross
authors.forename: Mayur M
authors.initials: MM
authors.lastname: Desai
authors.forename: Yuling
authors.initials: Y
authors.lastname: Hong
authors.forename: Augustus O
authors.initials: AO
authors.lastname: Grant
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Daniels
authors.forename: Vladimir C
authors.initials: VC
authors.lastname: Hachinski
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Gibbons
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Gardner
authors.forename: Harlan M
authors.initials: HM
authors.lastname: Krumholz
mesh_terms: D000043:Abstracting and Indexing; D017712:Peer Review, Research; D017594:Publication Bias