title: Trends in study methods used in undergraduate medical education research, 1969-2007.
abstract: BACKGROUND
  Evidence-based medical education requires rigorous studies appraising educational efficacy.
  
  
  OBJECTIVE
  To assess trends over time in methods used to evaluate undergraduate medical education interventions and to identify whether participation of medical education departments or centers is associated with more rigorous methods.
  
  
  METHODS
  The PubMed, Cochrane Controlled Trials Registry, Campbell Collaboration, and ERIC databases (January 1966-March 2007) were searched using terms equivalent to students, medical and education, medical crossed with all relevant study designs.
  
  
  METHODS
  We selected publications in all languages from every fifth year, plus the most recent 12 months, that evaluated an educational intervention for undergraduate medical students. Four hundred seventy-two publications met criteria for review.
  
  
  METHODS
  Data were abstracted on number of participants; types of comparison groups; whether outcomes assessed were objective, subjective, and/or validated; timing of outcome assessments; funding; and participation of medical education departments and centers. Ten percent of publications were independently abstracted by 2 authors to assess validity of the data abstraction.
  
  
  RESULTS
  The annual number of publications increased over time from 1 (1969-1970) to 147 (2006-2007). In the most recent year, there was a mean of 145 medical student participants; 9 (6%) recruited participants from multiple institutions; 80 (54%) used comparison groups; 37 (25%) used randomized control groups; 91 (62%) had objective outcomes; 23 (16%) had validated outcomes; 35 (24%) assessed an outcome more than 1 month later; 21 (14%) estimated statistical power; and 66 (45%) reported funding. In 2006-2007, medical education department or center participation, reported in 46 (31%) of the recent publications, was associated only with enrolling more medical student participants (P = .04); for all studies from 1969 to 2007, it was associated only with measuring an objective outcome (P = .048). Between 1969 and 2007, the percentage of publications reporting statistical power and funding increased; percentages did not change for other study features.
  
  
  CONCLUSIONS
  The annual number of published studies of undergraduate medical education interventions demonstrating methodological rigor has been increasing. However, considerable opportunities for improvement remain.
authors.affiliation: Division of General Internal Medicine, University of Washington School of Medicine, Seattle, USA. abaer@u.washington.edu
authors.forename: Amy
authors.initials: A
authors.lastname: Baernstein
authors.forename: Hillary K
authors.initials: HK
authors.lastname: Liss
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Carney
authors.forename: Joann G
authors.initials: JG
authors.lastname: Elmore
mesh_terms: D004504:Education, Medical, Undergraduate / Q000639:trends; D004521:Educational Measurement; D005069:Evaluation Studies as Topic; D019317:Evidence-Based Medicine; D011643:Publishing / Q000639:trends; D012106:Research / Q000639:trends; D012107:Research Design