title: Evaluation of computer support for prescribing (CAPSULE) using simulated cases.
abstract: OBJECTIVE
  To evaluate the potential effect of computer support on general practitioners' prescribing, and to compare the effectiveness of three different support levels.
  
  
  METHODS
  Crossover experiment with balanced block design.
  
  
  METHODS
  Random sample of 50 general practitioners (42 agreed to participate) from 165 in a geographically defined area of Oxfordshire.
  
  
  METHODS
  Doctors prescribed for 36 simulated cases constructed from real consultations. Levels of computer support were control (alphabetical list of drugs), limited support (list of preferred drugs), and full support (the same list with explanations available for suggestions).
  
  
  METHODS
  Percentage of cases where doctors ignored a cheaper, equally effective drug; prescribing score (a measure of how closely prescriptions matched expert recommendations); interview to elicit doctors' views of support system.
  
  
  RESULTS
  Computer support significantly improved the quality of prescribing. Doctors ignored a cheaper, equally effective drug in a median 50% (range 25%-75%) of control cases, compared with 36% (8%-67%) with limited support and 35% (0-67%) with full support (P < 0.001). The median prescribing score rose from 6.0 units (4.2-7.0) with control support to 6.8 (5.8 to 7.7) and 6.7 (5.6 to 7.8) with limited and full support (P < 0.001). Of 41 doctors, 36 (88%) found the system easy to use and 24 (59%) said they would be likely to use it in practice.
  
  
  CONCLUSIONS
  Computer support improved compliance with prescribing guidelines, reducing the occasions when doctors ignored a cheaper, equally effective drug. The system was easy to operate, and most participating doctors would be likely to use it in practice.
authors.affiliation: Department of Public Health and Primary Care, Radcliffe Infirmary, Oxford. robert.walton@public-health.oxford.ac.uk
authors.forename: R T
authors.initials: RT
authors.lastname: Walton
authors.forename: C
authors.initials: C
authors.lastname: Gierl
authors.forename: P
authors.initials: P
authors.lastname: Yudkin
authors.forename: H
authors.initials: H
authors.lastname: Mistry
authors.forename: M P
authors.initials: MP
authors.lastname: Vessey
authors.forename: J
authors.initials: J
authors.lastname: Fox
mesh_terms: D003658:Decision Making, Computer-Assisted; D016527:Drug Costs; D011307:Drug Prescriptions / Q000191:economics / Q000706:statistics & numerical data; D017723:Drug Utilization Review; D005194:Family Practice / Q000191:economics / Q000458:organization & administration*; D006801:Humans; D008131:London; D017063:Outcome Assessment, Health Care; D016544:Patient Simulation; D010818:Practice Patterns, Physicians'